<PAGE>   1

   As filed with the Securities and Exchange Commission on December 31, 1997
                                                       Registration No. 333-
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, DC  20549
                             ---------------------
                                    FORM S-3
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                             ---------------------
                             NATIONAL-OILWELL, INC.
             (Exact name of registrant as specified in its charter)

                    DELAWARE                            76-0475815
         (State or other jurisdiction of             (I.R.S. Employer
         incorporation or organization)            Identification No.)


                                5555 SAN FELIPE
                             HOUSTON, TEXAS  77056
                                 (713) 960-5100
    (Address, including zip code, and telephone number, including area code,
                  of registrant's principal executive offices)
                             ---------------------                  
                  
                  
                            PAUL M. NATION, ESQUIRE
                       VICE PRESIDENT AND GENERAL COUNSEL
                             NATIONAL-OILWELL, INC.
                                5555 SAN FELIPE
                             HOUSTON, TEXAS  77056
                                 (713) 960-5100
 (Name, address, including zip code, and telephone number, including area code,
                             of agent for service)
                             ---------------------
                                   Copies to:

                             DAVID R. KING, ESQUIRE
                          Morgan, Lewis & Bockius LLP
                             2000 One Logan Square
                     Philadelphia, Pennsylvania  19103-6993
                                 (215) 963-5000
                             ---------------------

APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:  As soon as
practicable after the effective date of this Registration Statement.

    If the only securities being registered on this form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box.  [ ]

    If any of the securities being registered on this form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than securities offered only in connection with dividend or
interest reinvestment plans, check the following box.  [x]

    If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act of 1933, please check the
following box and list the Securities Act registration statement number of the
earlier effective registration statement for the same offering.  [ ]
                                                                    ---------

    If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act of 1933, check the following box and list the
Securities Act registration statement number of the earlier effective
registration statement for the same offering.  [ ]
                                                  ---------

    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box.  [ ]

                        CALCULATION OF REGISTRATION FEE



<TABLE>
<CAPTION>
==============================================================================================================
   TITLE OF EACH CLASS                            PROPOSED MAXIMUM         PROPOSED
   OF SECURITIES TO BE        AMOUNT TO BE         OFFERING PRICE     MAXIMUM AGGREGATE         AMOUNT OF
       REGISTERED              REGISTERED         PRICE PER SHARE(1)   OFFERING PRICE(1)     REGISTRATION FEE
- --------------------------------------------------------------------------------------------------------------
  <S>                        <C>                      <C>                <C>                     <C>
  Common Stock, par          800,000 shares           $30.1875           $24,150,000             $7,125
  value $.01 per share
==============================================================================================================
</TABLE>



(1) Estimated solely for the purpose of calculating the registration fee in
    accordance with Rule 457(c) under the Securities Act of 1933 based on the
    average of the high and low prices reported on the New York Stock Exchange
    on December 26, 1997.

    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(a),
MAY DETERMINE.
================================================================================

<PAGE>   2
PROSPECTUS


                                 800,000 SHARES

                             NATIONAL-OILWELL, INC.

                                  COMMON STOCK


    The shares offered hereby (the "Shares") consist of shares of common stock,
$.01 par value per share ("Common Stock"), of National-Oilwell, Inc., a
Delaware corporation ("National-Oilwell" or the "Company"), which are being
offered by the selling stockholders listed herein under "Selling Stockholders"
(collectively, the "Selling Stockholders").  The Shares may be offered from
time to time by the Selling Stockholders.  All expenses of registration
incurred in connection herewith are being borne by the Company, but all selling
and other expenses incurred by a Selling Stockholder will be borne by the
Selling Stockholder.  The Company will not receive any of the proceeds from the
sale of the Shares by the Selling Stockholders.

    The Selling Stockholders have not advised the Company of any specific plans
for the distribution of the Shares covered by this Prospectus, but it is
anticipated that the Shares will be sold from time to time primarily in
transactions (which may include block transactions) on the New York Stock
Exchange at the market price then prevailing, although sales may also be made
in negotiated transactions or otherwise.  The Selling Stockholders and the
brokers and dealers through whom sale of the Shares may be made may be deemed
to be "underwriters" within the meaning of the Securities Act of 1933, as
amended (the "Securities Act"), and their commissions or discounts and other
compensation may be regarded as underwriters' compensation.  See "Plan of
Distribution."

    The Common Stock is traded on the New York Stock Exchange under the symbol
"NOI."  On December 30, 1997, the last reported sale price of the Common Stock
on the New York Stock Exchange was $33.31 per share.

    SEE "RISK FACTORS" BEGINNING ON PAGE 3 FOR A DISCUSSION OF CERTAIN
CONSIDERATIONS RELEVANT TO AN INVESTMENT IN THE COMMON STOCK OFFERED HEREBY.


 THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
      EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE
    SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION
         PASSED UPON THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY
            REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
                                      
                             ---------------------
               THE DATE OF THIS PROSPECTUS IS JANUARY ___, 1997.

<PAGE>   3
         Unless otherwise indicated, all information in this Prospectus (i)
assumes the exchange on a one-for-one basis of all exchangeable shares (the
"Exchangeable Shares") of Dreco Energy Services Ltd. ("Dreco") into shares of
Common Stock and (ii) reflects the Company's and Dreco's one-for-one stock
dividends paid on November 18, 1997.  Unless the context otherwise requires (i)
all references to "National-Oilwell" or the "Company" are to National-Oilwell,
Inc. and its subsidiaries, and give effect to the September 25, 1997 business
combination (the "Combination") with Dreco and (ii) all references to
activities of, and financial information with respect to, National-Oilwell are
presented on a combined basis, even with respect to periods prior to the
consummation of the Combination.


                                  THE COMPANY

         National-Oilwell is a worldwide leader in the design, manufacture and
sale of machinery, equipment and downhole products used in oil and gas drilling
and production, as well as in the distribution to the oil and gas industry of
maintenance, repair and operating products.  The Company manufactures and
assembles drilling machinery, including drawworks, mud pumps and power swivels
(also known as "top drives"), which are the major mechanical components of rigs
used to drill oil and gas wells, as well as masts, derricks and substructures,
which are used to support these mechanical components.  Many of these
components are designed specifically for applications in offshore, extended
reach and deep land drilling.  The Company estimates that approximately 65% of
the mobile offshore rig fleet and the majority of the world's larger land rigs
(2,000 horsepower and greater) manufactured in the last twenty years utilize
drawworks, mud pumps and other drilling machinery components manufactured by
the Company.

         As a result of the Combination, National-Oilwell has added a business
segment that designs and manufactures drilling motors and specialized drilling
tools for rent and for sale.  Drilling motors are essential components of
systems for horizontal, directional, extended reach and performance drilling.
Drilling tools include drilling jars, shock tools and other specialized
products.

         The Company also provides distribution services through its network of
approximately 120 distribution service centers located near major drilling and
production activity worldwide, but principally in the United States and Canada.
These distribution service centers stock and sell a variety of expendable items
for oilfield applications and spare parts for National-Oilwell equipment.  As
oil and gas companies and drilling contractors have refocused on their core
competencies and emphasized efficiency initiatives to reduce costs and capital
requirements, the Company's distribution services have expanded to offer
outsourcing and alliance arrangements that include comprehensive procurement,
inventory management and logistics support.

         National-Oilwell is incorporated in Delaware, with its principal
executive offices located at 5555 San Felipe, Houston, Texas 77056, and its
telephone number is (713) 960-5100.


                                  THE OFFERING


<TABLE>
<S>                                                                          <C>
Common Stock Offered by Selling Stockholders(1) . . . . . . . . . . . . .    800,000 shares
Common Stock to be Outstanding After the Offering   . . . . . . . . . . .    51,651,146 shares(1)
New York Stock Exchange Symbol  . . . . . . . . . . . . . . . . . . . . .    NOI
</TABLE>


(1)      Excludes 617,444 shares of Common Stock issuable at December 15, 1997
         upon exercise of outstanding options to purchase Common Stock and
         316,264 shares of Common Stock that will be issued in January 1999
         pursuant to the Company's Value Appreciation Plans.





                                       2

<PAGE>   4
                DISCLOSURE REGARDING FORWARD-LOOKING STATEMENTS

         This Prospectus contains, or has incorporated by reference,
forward-looking statements that address, among other things, statements under
"Prospectus Summary" and "Risk Factors" as well as in the Prospectus generally.
Although National-Oilwell believes that the expectations reflected in such
forward-looking statements are reasonable, it can give no assurance that such
expectations will prove to have been correct.  Important factors that could
cause actual results to differ materially from National-Oilwell's expectations
are disclosed under "Risk Factors" and in this Prospectus generally, as well as
in the documents incorporated by reference herein.


                                  RISK FACTORS

         The following risk factors, as well as the other information contained
in this Prospectus, should be considered carefully before purchasing the Common
Stock offered hereby.

DEPENDENCE ON OIL AND GAS INDUSTRY

         National-Oilwell's businesses are substantially dependent upon the
condition of the oil and gas industry and the industry's willingness to explore
for and produce oil and gas.  The degree of such willingness is generally
dependent upon the prevailing view of future product prices, which are
influenced by numerous factors affecting the supply and demand for oil and gas,
including the level of drilling activity, worldwide economic activity, interest
rates and the cost of capital, the development of alternate energy sources,
environmental regulation, tax policies, political requirements of national
governments, coordination by the Organization of Petroleum Exporting Countries
("OPEC") and the cost of producing oil and gas.  Any significant reduction in
demand for drilling services, in cash flows of drilling contractors or in rig
utilization rates below current levels could result in a drop in demand for
products manufactured and sold by National-Oilwell.

VOLATILITY OF OIL AND GAS PRICES

         Oil and gas prices and activity have been characterized by significant
volatility over the last twenty years.  Since 1986, spot oil prices (West Texas
Intermediate) have ranged from a low of approximately $11 per barrel in 1986 to
a high of approximately $40 per barrel in 1991; spot gas prices (Henry Hub)
have ranged from lows below $1.00 per mcf of gas in 1992 to highs above $3.00
per mcf in 1996 and 1997.  These price changes have caused numerous shifts in
the strategies and expenditure levels of oil and gas companies and drilling
contractors, particularly with respect to decisions to purchase major capital
equipment of the type manufactured by National-Oilwell.  Moreover, uncertainty
with respect to the stability and direction of future prices has often led to
deferral of such expenditures.  No assurance can be given as to the future
price levels of oil and gas or the volatility thereof, or that the future price
of oil and gas will be sufficient to support current levels of exploration and
production.

HIGHLY COMPETITIVE INDUSTRY

         The oilfield products and services industry is highly competitive.
The revenues and earnings of National-Oilwell can each be affected by
competitive actions such as price changes, introduction of new technologies and
products or improved availability and delivery.  National-Oilwell competes with
a large number of companies, some of which may offer certain more
technologically advanced products, possess greater financial resources and have
more extensive and diversified operations.

POTENTIAL PRODUCT LIABILITY AND WARRANTY CLAIMS

         Certain products of National-Oilwell are used in potentially hazardous
drilling, completion and production applications that can cause personal injury
or loss of life, damage to property, equipment or the environment and
suspension of operations.  National-Oilwell maintains insurance coverage in
such amounts and against such risks as it





                                       3

<PAGE>   5
believes to be in accordance with normal industry practice.  Such insurance
does not, however, provide coverage for all liabilities (including liabilities
for certain events involving pollution), and there can be no assurance that
such insurance will be adequate to cover all losses or liabilities that may be
incurred by National-Oilwell in its operations.  Moreover, no assurance can be
given that National-Oilwell will, in the future, be able to maintain insurance
at levels it deems adequate and at rates it considers reasonable or that
particular types of coverage will be available.  Litigation arising from a
catastrophic occurrence at a location where National-Oilwell's equipment and
services are used may, in the future, result in National-Oilwell being named as
a defendant in product liability or other lawsuits asserting potentially large
claims.  National-Oilwell is a party to various legal and administrative
proceedings which have arisen from its businesses.  No assurance can be given
with respect to the outcome of these or any other pending legal and
administrative proceedings and the effects such outcomes may have on
National-Oilwell.

IMPACT OF GOVERNMENTAL REGULATIONS

         Many aspects of National-Oilwell's operations are affected by
political developments, including restrictions on the ability to do business in
various foreign jurisdictions, and are subject to both domestic and foreign
governmental regulation, including those relating to oilfield operations,
worker safety and the protection of the environment.  In addition,
National-Oilwell depends on the demand for its services from the oil and gas
industry and, therefore, is affected by any changes in taxation, price controls
or other laws and regulations that affect the oil and gas industry generally.
The adoption of laws and regulations curtailing exploration for or production
of oil and gas for economic or other policy reasons could adversely affect
National-Oilwell's operations.  National-Oilwell cannot determine the extent to
which its future operations and earnings may be affected by political
developments, new legislation, new regulations or changes in existing
regulations.

IMPACT OF ENVIRONMENTAL REGULATIONS

         The operations of National-Oilwell and its customers are affected by
numerous foreign, federal, state, provincial and local environmental laws and
regulations.  The technical requirements of these laws and regulations are
becoming increasingly expensive, complex and stringent.  These laws may impose
penalties or sanctions for damages to natural resources or threats to public
health and safety.  Such laws and regulations may also expose National-Oilwell
to liability for the conduct of or conditions caused by others, or for acts of
National-Oilwell that were in compliance with all applicable laws at the time
such acts were performed.  Sanctions for noncompliance may include revocation
of permits, corrective action orders, administrative or civil penalties and
criminal prosecution.  Certain environmental laws provide for joint and several
liability for remediation of spills and releases of hazardous substances.  In
addition, National-Oilwell may be subject to claims alleging personal injury or
property damage as a result of alleged exposure to hazardous substances, as
well as damage to natural resources.

RISK OF CERTAIN FOREIGN MARKETS

         Certain of National-Oilwell's revenues result from the sale of
products to customers for ultimate destinations in the Middle East, Africa and
other international markets and are subject to risks of instability of foreign
economies and governments.  Furthermore, National-Oilwell's sales can be
affected by laws and regulations limiting exports to particular countries.  In
certain cases, export laws and regulations of one jurisdiction may contradict
those of another.

         National-Oilwell attempts to limit its exposure to foreign currency
fluctuations by limiting the amount of sales denominated in currencies other
than United States dollars, Canadian dollars and British pounds.
National-Oilwell has not engaged in and does not currently intend to engage in
any significant hedging or currency trading transactions designed to compensate
for adverse currency fluctuations among those or any other foreign currencies.

INTEGRATION OF ACQUISITIONS AND MANAGEMENT OF GROWTH

         National-Oilwell consummated the Combination with Dreco in September
1997 and expects to evaluate and, where feasible, make additional strategic
acquisitions in the future.  There is no guarantee that the Company will not





                                       4

<PAGE>   6
encounter integration difficulties or that it will extract any anticipated cost
savings and margin enhancements.  In addition, the process of combining the
organizations could cause the interruption of, or a loss of momentum in, the
activities of some or all of the companies' businesses, which could have an
adverse effect on their combined operations.  The Combination and recent growth
in revenues and backlog have placed significant demands on the Company and its
management to improve the combined entity's operational, financial and
management information systems, to develop further the management skills of the
Company's managers and supervisors, and to continue to train, motivate and
effectively manage the Company's employees.  The failure of the Company to
manage its growth effectively could have a material adverse effect on the
Company.

         The Company has pursued an aggressive acquisition strategy, acquiring
three businesses in 1997, and expects to continue to evaluate acquisitions that
can provide meaningful benefits by expanding the Company's business and
leveraging its existing infrastructure.  However, there are various risks
associated with pursuing an acquisition strategy of this nature, including
problems inherent in integrating new businesses. There can be no assurance that
suitable acquisition candidates will be available, that acquisitions can be
completed on reasonable terms, that the Company will successfully integrate the
operations of any acquired entities or that the Company will have access to
adequate funds to effect any desired acquisitions.

CERTAIN ANTI-TAKEOVER PROVISIONS COULD DISCOURAGE UNSOLICITED PROPOSALS

         The Company's Amended and Restated Certificate of Incorporation (the
"Certificate of Incorporation") and Bylaws contain certain provisions which may
have the effect of delaying, deferring or preventing a change in control of the
Company, including a classified board of directors, the removal of directors
from office only for cause, the prohibition of stockholder action by written
consent, advance notice requirements respecting stockholder nominations for
director or any other matter, the number of directors being set by the board of
directors, super majority voting provisions respecting certain amendments to
the Certificate of Incorporation and limitation of persons who may call special
stockholders' meetings.  The Delaware General Corporation Law requires super
majority voting thresholds to approve certain "business combinations" between
interested stockholders and the Company which may render more difficult or tend
to discourage attempts to acquire the Company.  In addition, the Company's
board of directors has the authority to issue shares of preferred stock
("Preferred Stock") in one or more series and to fix the rights and preferences
of the shares of any such series without stockholder approval.  Any series of
Preferred Stock is likely to be senior to the Common Stock with respect to
dividends, liquidation rights and, possibly, voting rights.  The ability to
issue Preferred Stock could also have the effect of discouraging unsolicited
acquisition proposals, thus affecting the market price of the Common Stock and
preventing stockholders from obtaining any premium offered by the potential
buyer.

NO ANTICIPATED DIVIDENDS

         The Company's board of directors has not previously authorized and
does not currently anticipate authorizing in the foreseeable future the payment
of cash dividends.


                                USE OF PROCEEDS

         All of the shares of Common Stock are being offered by the Selling
Stockholders.  National-Oilwell will not receive any of the proceeds from the
sale of such shares of Common Stock in the Offering.





                                       5

<PAGE>   7
                                    BUSINESS

GENERAL

         National-Oilwell is a worldwide leader in the design, manufacture and
sale of machinery, equipment and downhole products used in oil and gas drilling
and production, as well as in the distribution to the oil and gas industry of
maintenance, repair and operating products.

         The Company manufactures and assembles drilling machinery, including
drawworks, mud pumps and power swivels (also known as "top drives"), which are
the major mechanical components of rigs used to drill oil and gas wells, as
well as masts, derricks and substructures, which are used to support these
mechanical components.  Many of these components are designed specifically for
applications in offshore, extended reach and deep land drilling.  As a result
of the Combination, National-Oilwell has added a business segment that designs
and manufactures drilling motors and specialized drilling tools for rent and
for sale.  Drilling motors are essential components of systems for horizontal,
directional, extended reach and performance drilling.  Drilling tools include
drilling jars, shock tools and other specialized products.  In addition,
National-Oilwell provides distribution services through its network of
distribution service centers.

         In April 1987, National-Oilwell's predecessor was formed as a
partnership to consolidate two oilfield equipment manufacturing and
distribution operations, each of which had been a leader in the oilfield
equipment and distribution businesses since the late 1800s.  Certain members of
management and an investor group incorporated National-Oilwell, Inc. as a
Delaware corporation and purchased the business of the partnership in January
1996.  In October 1996, National-Oilwell sold 9,200,000 shares of its Common
Stock in an initial public offering and listed its shares on the New York Stock
Exchange.

         On September 25, 1997, National-Oilwell completed the Combination with
Dreco.  Pursuant to the Combination Agreement, dated as of May 14, 1997, as
amended, by and between National-Oilwell and Dreco, each holder of Dreco Common
Shares prior to the transaction received .9159 Dreco Exchangeable Shares in
exchange for each of their Dreco Common Shares.  Each Exchangeable Share is
intended to have substantially identical economic and legal rights as, and will
ultimately be exchanged for, a share of National-Oilwell Common Stock.

         National-Oilwell believes that the Combination with Dreco enhances the
ability of National-Oilwell to compete in the oilfield products and services
industry.  Specifically, the combined companies have the ability to provide a
more complete rig package to customers through the combination of
National-Oilwell's oilfield equipment operations (which had emphasized the
major machinery components of a drilling rig) and Dreco's oilfield equipment
operations (which had emphasized the design and construction of derricks, masts
and substructures).  In addition, the combination of Dreco's engineering
expertise with the size, geographical coverage and after-market support of
National-Oilwell is attractive to many customers.  National-Oilwell also added
Dreco's downhole products business as a business segment and may benefit from
the ability of the combined company to market and deliver Dreco's line of
downhole products through National-Oilwell's extensive marketing and
distribution system.

         On May 15, 1997, National-Oilwell acquired by merger 100% of the
common stock of PEP, Inc., a manufacturer of petroleum expendable pump products
that are similar to those manufactured by National-Oilwell.  This acquisition
provides a broader line of products as well as additional manufacturing
capacity.  On April 25, 1997, National-Oilwell purchased the drilling controls
business of Ross Hill Controls, a leader in the manufacture, sale and service
of innovative electrical control systems, including silicon controlled
rectifier ("SCR") houses, used in conjunction with drilling operations.  These
products are closely associated with and complementary to other components used
in connection with the drilling process and allow National-Oilwell to offer a
more complete rig package.  On December 2, 1996, Dreco acquired 100% of the
issued and outstanding shares of Vector Oil Tool Ltd., which manufactures,
sells, rents and services downhole motors and other products.





                                       6

<PAGE>   8
OPERATIONS

  Products and Technology

         National-Oilwell designs, manufactures and sells the major mechanical
components for both land and offshore rigs used to drill oil and gas wells as
well as complete land drilling and well servicing rigs.  The mechanical
components include drawworks, mud pumps, power swivels, SCR houses, traveling
equipment and rotary tables.  These are the major components involved in the
primary functions of the drilling of oil and gas wells, which consist of
pumping fluids and hoisting, supporting and rotating the drill string.  Many of
these components are designed specifically for applications in offshore,
extended reach and deep land drilling.  This equipment is installed on new rigs
and used in the upgrade, refurbishment and repair of existing rigs.  While
offering a complete line of conventional rigs, National-Oilwell has extensive
experience in providing rig designs to satisfy requirements for harsh or
specialized environments.  Such products include North Slope of Alaska and
Arctic drilling and well servicing rigs, highly mobile drilling and well
servicing rigs for jungle and desert use, modular well servicing rigs for
offshore platforms and modular drilling facilities for North Sea platforms.
Masts, derricks and substructures are made for use on land rigs and on fixed
and mobile offshore platforms and are suitable for drilling to maximum depths
ranging up to more than 30,000 feet.  Other products include pedestal cranes,
reciprocating and centrifugal pumps and fluid end expendables for all major
manufacturers' pumps.

         National-Oilwell's business includes the sale of replacement parts for
its own manufactured machinery and equipment.  National-Oilwell estimates that
approximately 65% of the mobile offshore rig fleet and the majority of the
world's larger land rigs (2,000 horsepower and greater) manufactured in the
last twenty years utilize drawworks, mud pumps and other drilling machinery
components manufactured by National-Oilwell.  In addition, National-Oilwell
manufactures and sells centrifugal and reciprocating pumps used in oilfield and
industrial applications.

  Downhole Products

         National-Oilwell designs and manufactures drilling motors and
specialized drilling tools for rent and sale.  Rentals generally involve
products that are not economical for a customer to own or maintain because of
the broad range of equipment required for the diverse hole size and depths
encountered in drilling for oil and gas.  Sales generally involve products that
require infrequent service, are disposable or are sold in countries where
National-Oilwell does not provide repair and maintenance services.

         National-Oilwell's drilling motors are devices placed between the
drill string and the drill bit to cause the bit to rotate without necessarily
rotating the drill string.  Drilling motors are essential components in systems
for horizontal, directional, extended reach and performance drilling.

         National-Oilwell often rents its drilling motors, retaining control
over the servicing and maintenance function so as to preserve their operating
reliability.  National-Oilwell is continuing to enhance and broaden the range
of its drilling motors by, among other things, widening the size range offered,
reducing the initial cost and ongoing repair and maintenance cost, and
developing alternative designs of motor bearing assembly sealing systems and
speed reduction systems.

         National-Oilwell manufactures hydraulic-mechanical and mechanical
drilling jars and shock tools.  Drilling jars are used to assist in releasing a
drill string that becomes stuck in a well bore.  A shock tool is a downhole
shock absorber placed low in the drill string, often directly above the drill
bit when rotary drilling in formations that are hard and abrasive.  Shock tools
are intended to extend bit life, reduce drill string failures and reduce damage
to the drilling rig.  National-Oilwell also manufactures and rents or sells
fishing jars, jar accelerators, bumper subs, reamers, stabilizers, kelly and
tubing safety valves and drill string inside blowout preventers.





                                       7

<PAGE>   9
  Distribution Services

         National-Oilwell provides distribution services through its network of
distribution service centers located near major drilling and production
activity worldwide, but principally in the United States and Canada.  These
distribution service centers stock and sell a variety of expendable items for
oilfield applications and spare parts for National-Oilwell equipment.  As oil
and gas companies and drilling contractors have refocused on their core
competencies and emphasized efficiency initiatives to reduce costs and capital
requirements, National-Oilwell's distribution services have expanded to offer
outsourcing and alliance arrangements that include comprehensive procurement,
inventory management and logistics support.  In addition, management believes
that National-Oilwell has a competitive advantage in the distribution services
business by distributing market-leading products manufactured by its Products
and Technology business.

         The supplies and equipment stocked by National-Oilwell's distribution
service centers vary by location.  Each distribution point generally offers a
large line of oilfield products including valves, fittings, flanges, spare
parts for oilfield equipment and miscellaneous expendable items.  Most drilling
contractors and oil and gas companies typically buy such supplies and equipment
pursuant to non-exclusive contracts, which normally specify a discount from
National-Oilwell's list price for each product or product category.

         National-Oilwell's tubular business is focused on the procurement,
inventory management and delivery of oil country tubular goods manufactured by
third parties.  Tubular goods primarily consist of well casing and production
tubing used in the drilling, completion and production of oil and gas wells.
Well casing is used to line the walls of a well bore to provide structural
support.  Production tubing provides the conduit through which the oil or gas
will be brought to the surface upon completion of the well.  Historically,
sales of tubular goods have been concentrated in North America, although
National-Oilwell makes occasional sales for shipment to foreign destinations.
Substantially all of National-Oilwell's sales of tubular goods are made through
National-Oilwell's direct sales force.

         As a result of efficiency initiatives that are taking place in the oil
and gas industry, drilling contractors and oil and gas companies are more
frequently seeking strategic alliances and outsourcing their procurement and
inventory management requirements.  These strategic alliances constitute a
growing percentage of National-Oilwell's business and differ from standard
agreements for supplies and equipment in that National-Oilwell becomes the
customer's primary supplier of those items.  In certain cases, National-Oilwell
has assumed responsibility for procurement, inventory management and product
delivery for the customer, occasionally by working directly out of the
customer's facilities.

MARKETING

         Substantially all of National-Oilwell's drilling machinery, equipment
and spare parts sales and a large portion of National-Oilwell's pumps and parts
are sold through National-Oilwell's direct sales force and through
National-Oilwell's distribution service centers.  National-Oilwell also markets
its pumps and parts through distribution networks not owned by
National-Oilwell.  Sales to foreign state-owned oil companies are typically
made in conjunction with agent or representative arrangements.
National-Oilwell's downhole products are rented in Canada and Venezuela and
marketed worldwide through its own sales force and through commission
representatives.  Customers include drilling contractors, exploration and
production companies, supply companies and nationally owned or controlled
drilling and production companies.

COMPETITION

         The oilfield equipment industry is highly competitive and
National-Oilwell's revenues and earnings can be affected by price changes,
introduction of new technologies and products and improved availability and
delivery.  National-Oilwell competes in one or more of its segments with a
large number of companies, including Continental Emsco Company (Products and
Technology and Distribution Services), IRI International Corporation (Products
and Technology) and Wilson Industries, Inc. (Downhole Products and Distribution
Services).





                                       8

<PAGE>   10
MANUFACTURING AND BACKLOG

         National-Oilwell's principal manufacturing facilities are located in
Houston, Texas, Clearfield, Utah, McAlester, Oklahoma and Edmonton, Alberta,
Canada.  National-Oilwell also outsources the manufacture of parts or purchases
components in finished form from qualified subcontractors.  National-Oilwell's
manufacturing operations require a variety of components, parts and raw
materials which National-Oilwell purchases from multiple commercial sources.
National-Oilwell has not experienced and does not expect any significant delays
in obtaining deliveries of essential components, parts or raw materials.

         Sales of National-Oilwell's products are made on the basis of written
orders and oral commitments.  The level of backlog at any particular time is
not necessarily indicative of the future operating performance of the Company,
and orders may be changed at any time.  Substantially all of the current
backlog will be shipped by the end of 1998.

ENGINEERING

         National-Oilwell maintains a staff of engineers and technicians to (i)
design and test new products, components and systems for use in drilling and
pumping applications, (ii) enhance the capabilities of existing products and
(iii) assist National-Oilwell's sales organization and customers with special
projects.  National-Oilwell's product engineering efforts focus on developing
technology to improve the economics and safety of drilling and pumping
processes.  National-Oilwell has recently developed a 1,000-ton capacity power
swivel to complement its lower capacity models.  National-Oilwell has also
introduced a 6,000 horsepower heave compensating drawworks and dual derrick
systems to increase customer efficiencies on deep water drilling rigs at
extended depths and during horizontal drilling.

PATENTS AND TRADEMARKS

         National-Oilwell owns or has a license to use a number of patents
covering a variety of products.  Although in the aggregate these patents are of
importance, National-Oilwell does not consider any single patent to be of a
critical or essential nature.  In general, National-Oilwell depends on
technological capabilities, quality products and application of its expertise
rather than patented technology in the conduct of its business.
National-Oilwell enjoys significant product name-brand recognition, principally
through its NATIONAL-OILWELL(R), DRECO(R), ROSS HILL, TRUDRIL(R), VECTOR,
GRIFFITH(R) and MISSION-FLUID KING trade names.

DISTRIBUTION SUPPLIERS

         National-Oilwell obtains products sold by its Distribution Services
business from a number of suppliers, including the Company's Products and
Technology segment.  National-Oilwell does not believe that any one supplier of
products is material to National-Oilwell.  For the year ended December 31,
1996, National-Oilwell purchased approximately one third of its tubular
requirements pursuant to a distribution agreement with the U.S. Steel Group of
USX Corporation, and its remaining requirements from various suppliers.
National-Oilwell has not experienced and does not foresee experiencing a
shortage in products or tubular goods sold by National-Oilwell, although order
lead times for tubular goods have increased over the last six months due to
higher demand for these products.





                                       9

<PAGE>   11
                              SELLING STOCKHOLDERS


         The following table sets forth certain information with respect to the
beneficial ownership of the Common Stock as of December 15, 1997 and as
adjusted to reflect the sale of the shares offered hereby.  This information
has been provided by each of the Selling Stockholders as of December 15, 1997,
at the request of National-Oilwell.  There are no shares of Common Stock
subject to stock options granted to the Selling Stockholders that are
exercisable within 60 days of December 15, 1997.

         The Selling Stockholders, or their pledgees, donees, transferees or
other successors in interest, may offer the Shares for resale from time to
time.  See "Plan of Distribution."  In recognition of the fact that Selling
Stockholders may wish to be legally permitted to sell their Shares when they
deem appropriate, the Company has filed with the Commission under the
Securities Act a Registration Statement on Form S-3, of which this Prospectus
forms a part, with respect to the resale of the Shares from time to time on the
New York Stock Exchange or in privately-negotiated transactions and has agreed
to prepare and file such amendments and supplements to the Registration
Statement as may be necessary to keep the Registration Statement effective
until the earlier of (i) the date the Shares are no longer required to be
registered for the sale thereof by the Selling Stockholders or (ii) seven
months from the effective date of the Registration Statement.


<TABLE>
<CAPTION>
                                           SHARES BENEFICIALLY           SHARES         SHARES BENEFICIALLY 
                                            OWNED PRIOR TO               BEING          OWNED SUBSEQUENT TO
                                              OFFERING(1)               OFFERED(2)          OFFERING(1)       
                                         -----------------------        ----------   ---------------------------

NAME OF SELLING STOCKHOLDER(3)           NUMBER          PERCENT                        NUMBER        PERCENT
- ------------------------------           ------          -------                        ------        -------
<S>                                     <C>                 <C>         <C>               <C>            <C>
Billy R. Hext                           509,600             *           509,600           0              *
B.D. Berryhill                          274,400             *           274,400           0              *
Dillco, Inc.                              16,000            *            16,000           0              *

TOTAL SHARES BEING OFFERED                                              800,000
                                                                        =======

</TABLE>


________________
*  Less than one percent.

(1)      Based on 51,651,146 shares of Common Stock outstanding at December 15,
         1997.
(2)      This Registration Statement includes shares of Common Stock which may
         be sold by pledgees, donees, transferees or other  successors in
         interest of the listed Selling Stockholders.  The Selling Stockholders
         have agreed not to transfer in the aggregate Shares representing more
         than one percent of the Company's outstanding shares of Common Stock
         as of the date hereof to any such persons.
(3)      None of the Selling Stockholders have any relationship to the Company
         other than as stockholders of the Company.





                                       10

<PAGE>   12
                              PLAN OF DISTRIBUTION


         The Shares offered hereby by the Selling Stockholders may be sold from
time to time by the Selling Stockholders, or by pledgees, donees, transferees
or other successors in interest.  The Selling Stockholders have agreed not to
transfer in the aggregate Shares representing more than one percent of the
Company's outstanding shares of Common Stock as of the date hereof to any such
persons.  Such sales may be made on one or more exchanges (including the New
York Stock Exchange), in the over-the-counter market or otherwise at prices and
at terms then prevailing or at prices related to the then-current market price,
or in negotiated transactions.  The Shares may be sold by one or more of the
following methods, including, without limitation:  (a) a block trade in which
the broker-dealer so engaged will attempt to sell the Shares as agent but may
position and resell a portion of the block as principal to facilitate the
transaction; (b) purchases by a broker or dealer as principal and resale by
such broker or dealer for its account pursuant to this Prospectus; (c) ordinary
brokerage transactions and transactions in which the broker solicits
purchasers; and (d) face-to-face transactions between a Selling Stockholder and
purchasers without a broker-dealer.  In effecting sales, brokers or dealers
engaged by a Selling Stockholder may arrange for other brokers or dealers to
participate.  Such brokers or dealers may receive commissions or discounts from
a Selling Stockholder in amounts to be negotiated immediately prior to the
sale.  Such brokers or dealers and any other participating brokers or dealers
may be deemed to be "underwriters" within the meaning of the Securities Act, in
connection with such sales.  In addition, any securities covered by this
Prospectus that qualify for sale pursuant to Rule 144 might be sold under Rule
144 rather than pursuant to this Prospectus.

         Upon the Company's being notified by a Selling Stockholder that any
material arrangement has been entered into with a broker or dealer for the sale
of shares through a block trade, special offering, exchange distribution or
secondary distribution or a purchase by a broker or dealer, a supplemented
Prospectus will be filed, if required, pursuant to Rule 424(c) under the
Securities Act, disclosing (a) the name of each such broker or dealer, (b) the
number of shares involved, (c) the price at which such shares were sold, (d)
the commissions paid or discounts or concessions allowed to such broker(s) or
dealer(s), where applicable, (e) that such broker(s) or dealer(s) did not
conduct any investigation to verify the information set out or incorporated by
reference in this Prospectus, as supplemented, and (f) other facts material to
the transaction.

         The Company is bearing all costs relating to the registration of the
Shares (other than fees and expenses, if any, of counsel or other advisers to
the Selling Stockholders).  Any commissions, discounts or other fees payable to
broker-dealers in connection with any sale of the Shares will be borne by the
Selling Stockholder selling such Shares.





                                       11

<PAGE>   13
                                 LEGAL MATTERS


         The validity of the Common Stock offered hereby will be passed upon
for National-Oilwell by Morgan, Lewis & Bockius LLP, Philadelphia,
Pennsylvania.


                                    EXPERTS


         The consolidated financial statements of National-Oilwell at December
31, 1996 and for the year then ended, appearing in National-Oilwell's Current
Report on Form 8-K dated November 7, 1997 have been audited by Ernst & Young
LLP, independent auditors, as set forth in their report thereon, included
therein, and incorporated by reference elsewhere herein which is based in part
on the report of Coopers & Lybrand, independent auditors.  The financial
statements referred to above are included in reliance upon such reports given
upon the authority of such firms as experts in accounting and auditing.

         The consolidated financial statements of National-Oilwell at August
31, 1995 and for each of the two years in the period ended August 31, 1995,
appearing in National-Oilwell's Current Report on Form 8-K dated November 7,
1997 have been audited by Coopers & Lybrand, independent auditors, as set forth
in their report thereon and incorporated by reference elsewhere herein, and are
included in reliance upon such report given upon the authority of such firm as
experts in accounting and auditing.


                             AVAILABLE INFORMATION


         National-Oilwell is subject to the reporting requirements of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), and in
accordance therewith files reports, proxy statements and other information with
the Securities and Exchange Commission (the "Commission").  Such reports, proxy
statements and other information can be inspected and copied at the public
reference facilities maintained by the Commission at Room 1024, Judiciary
Plaza, 450 Fifth Street, N.W., Washington, D.C.  20549, as well as the
following Regional Offices of the Commission: Seven World Trade Center, 13th
Floor, New York, New York 10048; and Citicorp Center, 500 West Madison Street,
Suite 1400, Chicago, Illinois 60661.  Copies of such material can be obtained
from the Public Reference Section of the Commission at Room 1024, Judiciary
Plaza, 450 Fifth Street, N.W., Washington, D.C.  20549 at prescribed rates.
Such material also may be accessed electronically by means of the Commission's
home page on the Internet (http://www.sec.gov).  In addition, such reports,
proxy statements and other information concerning National-Oilwell can be
inspected and copied at the offices of the New York Stock Exchange, 20 Broad
Street, New York, New York 10005.

         This Prospectus constitutes a part of a registration statement on Form
S-3 (herein, together will all exhibits and schedules thereto, referred to as
this "Registration Statement") filed by National-Oilwell with the Commission
under the Securities Act, with respect to the securities offered hereby.  This
Prospectus does not contain all the information set forth in the Registration
Statement, certain parts of which are omitted in accordance with the rules and
regulations of the Commission.  Reference is hereby made to the Registration
Statement for further information with respect to National-Oilwell and the
securities offered hereby.  Copies of the Registration Statement are on file at
the offices of the Commission and may be obtained upon payment of the
prescribed fee or may be examined without charge at the public reference
facilities of the Commission described above.  Statements contained herein
concerning the provisions of documents are necessarily summaries of such
documents, and each statement is qualified in its entirety by reference to the
copy of the applicable document filed with the Commission.





                                       12

<PAGE>   14
                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE


         The following documents filed with the Commission pursuant to the
Exchange Act are incorporated by reference in this Prospectus:

                 1.  National-Oilwell's Annual Report on Form 10-K for the
         fiscal year ended December 31, 1996, as amended by Form 10-K/A filed
         on August 18, 1997.

                 2.  National-Oilwell's Quarterly Report on Form 10-Q for the
                     period ended March 31, 1997.

                 3.  National-Oilwell's Quarterly Report on Form 10-Q for the
                     period ended June 30, 1997.

                 4.  National-Oilwell's Quarterly Report on Form 10-Q for the
                     period ended September 30, 1997.

                 5.  National-Oilwell's Current Report on Form 8-K filed on May
                     25, 1997.

                 6.  National-Oilwell's Current Report on Form 8-K filed on
                     October 8, 1997.

                 7.  National-Oilwell's Current Report on Form 8-K filed on
                     November 7, 1997.

                 8.  The description of National-Oilwell's shares of Common
         Stock contained in the Registration Statement on Form 8-A filed by
         National-Oilwell with the Commission on October 15, 1996 to register
         such securities under the Exchange Act, as updated by
         National-Oilwell's Current Report on Form 8-K filed on November 17,
         1997.

         All reports and documents filed by National-Oilwell pursuant to
Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act after the date of this
Registration Statement and prior to the filing of a post-effective amendment to
this Registration Statement which indicates that all securities offered hereby
have been sold or which deregisters all securities then remaining unsold, shall
be deemed to be incorporated by reference in this Registration Statement and to
be a part hereof from the date of filing of such documents.  Any statement
contained in a document incorporated by reference herein shall be deemed to be
modified or superseded for purposes hereof to the extent that a statement
contained herein (or in any other subsequently filed document which also is
incorporated by reference herein) modifies or supersedes such statement.  Any
statement so modified or superseded shall not be deemed to constitute a part
hereof except as so modified or superseded.

         Upon request, National-Oilwell will provide without charge to each
person to whom this Prospectus is delivered a copy of any or all of such
documents which are incorporated herein by reference (other than exhibits to
such documents unless such exhibits are specifically incorporated by reference
into the documents that this Prospectus incorporates).  Written or oral
requests for copies should be directed to Gay Mather, Manager, Investor
Relations, National-Oilwell, Inc., 5555 San Felipe, Houston, Texas 77056
(telephone number (713) 960-5422).





                                       13

<PAGE>   15

================================================================================
     NO DEALER, SALESPERSON, OR OTHER INDIVIDUAL HAS BEEN AUTHORIZED TO GIVE
ANY INFORMATION OR TO MAKE ANY REPRESENTATIONS OTHER THAN THOSE CONTAINED, OR
INCORPORATED BY REFERENCE, IN THIS PROSPECTUS IN CONNECTION WITH THE OFFERING
COVERED BY THIS PROSPECTUS AND, IF GIVEN OR MADE, SUCH INFORMATION OR
REPRESENTATIONS MUST NOT BE RELIED UPON AS HAVING BEEN AUTHORIZED BY THE
COMPANY OR THE SELLING STOCKHOLDERS.  THIS PROSPECTUS DOES NOT CONSTITUTE AN
OFFER TO SELL, OR A SOLICITATION OF AN OFFER TO BUY, ANY SECURITIES OTHER THAN
THOSE SPECIFICALLY OFFERED HEREBY IN ANY JURISDICTION TO ANY PERSONS TO WHOM IT
IS UNLAWFUL TO MAKE SUCH OFFER OR SOLICITATION IN SUCH JURISDICTION.  NEITHER
THE DELIVERY OF THIS PROSPECTUS NOR ANY SALE MADE HEREUNDER SHALL, UNDER ANY
CIRCUMSTANCES, CREATE ANY IMPLICATION THAT THE INFORMATION HEREIN IS CORRECT AS
OF ANY TIME SUBSEQUENT TO ITS DATE.

                               -----------------


                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                       PAGE
                                                       ----
<S>                                                      <C>
The Company . . . . . . . . . . . . . . . . . . . . . .   2
The Offering  . . . . . . . . . . . . . . . . . . . . .   2
Disclosure Regarding Forward-Looking
   Statements . . . . . . . . . . . . . . . . . . . . .   3
Risk Factors  . . . . . . . . . . . . . . . . . . . . .   3
Use of Proceeds . . . . . . . . . . . . . . . . . . . .   5
Business  . . . . . . . . . . . . . . . . . . . . . . .   6
Selling Stockholders  . . . . . . . . . . . . . . . . .  10
Plan of Distribution  . . . . . . . . . . . . . . . . .  11
Legal Matters . . . . . . . . . . . . . . . . . . . . .  12
Experts . . . . . . . . . . . . . . . . . . . . . . . .  12
Available Information . . . . . . . . . . . . . . . . .  12
Incorporation of Certain Documents
   by Reference . . . . . . . . . . . . . . . . . . . .  13
</TABLE>

================================================================================

================================================================================
                                 800,000 SHARES


                             NATIONAL-OILWELL, INC.


                                  COMMON STOCK


                      ------------------------------------

                                   PROSPECTUS

                      ------------------------------------


                               JANUARY    , 1997
                                       ---

================================================================================



<PAGE>   16

                                    PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS


14.      OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION

         The expenses of the Offering are estimated to be as follows:


<TABLE>
         <S>                                                                                      <C>
         Securities and Exchange Commission Registration Fee  . . . . . . . . . . . . . . . . .   $   7,125
         Printing Expenses  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .         500
         Legal Fees and Expenses  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .      10,000
         Accounting Fees and Expenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . .      10,000 
                                                                                                   --------
                 Total  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .      27,625 
                                                                                                   ========
</TABLE>


15.      INDEMNIFICATION OF DIRECTORS AND OFFICERS

         Section 145 of the Delaware General Corporation Law (the "DGCL")
authorizes, inter alia, a corporation to indemnify any person who was or is a
party or is threatened to be made a party to any threatened, pending or
completed action, suit or proceeding, whether civil, criminal, administrative
or investigative (other than an action by or in the right of the corporation),
by reason of the fact that such person is or was an officer or director of such
corporation, or is or was serving at the request of such corporation as a
director, officer, employee or agent of another corporation, partnership, joint
venture, trust or other enterprise.  The indemnity may include expenses
(including attorneys' fees), judgments, fines and amounts paid in settlement
actually and reasonably incurred by such person in connection with such action,
suit or proceeding, provided that he acted in good faith and in a manner he
reasonably believed to be in or not opposed to the best interests of the
corporation and, with respect to any criminal action or proceeding, had no
reasonable cause to believe his conduct was unlawful.  A Delaware corporation
may indemnify past or present officers and directors of such corporation or of
another corporation or other enterprise at the former corporation's request, in
an action by or in the right of the corporation to procure a judgment in its
favor under the same conditions, except that no indemnification is permitted
without judicial approval if such person is adjudged to be liable to the
corporation.  Where an officer or director is successful on the merits or
otherwise in defense of any action referred to above, or in defense of any
claim, issue or matter therein, the corporation must indemnify him against the
expenses (including attorney's fees) which he actually and reasonably incurred
in connection therewith.  Section 145 further provides that any indemnification
shall be made by the corporation only as authorized in each specific case upon
a determination by the (i) stockholders, (ii) board of directors by a majority
vote of a quorum consisting of directors who were not parties to such action,
suit or proceeding or (iii) independent counsel if a quorum of disinterested
directors so directs.  Section 145 provides that indemnification pursuant to
its provisions is not exclusive of other rights of indemnification to which a
person may be entitled under any bylaw, agreement, vote of stockholders or
disinterested directors or otherwise.

         Section 145 of the DGCL also empowers National-Oilwell to purchase and
maintain insurance on behalf of any person who is or was an officer or director
of National-Oilwell against liability asserted against or incurred by him in
any such capacity, whether or not National-Oilwell would have the power to
indemnify such officer or director against such liability under the provisions
of Section 145.  National-Oilwell maintains a directors' and officers'
liability policy for such purposes.

         Article Sixth, Part II, Section 1 of National-Oilwell's Amended and
Restated Certificate of Incorporation and Article VI of National-Oilwell's
Bylaws each provide that directors, officers, employees and agents shall be
indemnified to the fullest extent permitted by Section 145 of the DGCL.





                                      II-1

<PAGE>   17
16.      EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

         (a)  Exhibits.  The following exhibits are filed as part of this
Registration Statement.


<TABLE>
<CAPTION>
EXHIBIT
NUMBER   DESCRIPTION
- ------   -----------
<S>      <C>     <C>
5        --      Opinion of Morgan, Lewis & Bockius LLP regarding legality of securities being registered
23.1     --      Consent of Ernst & Young LLP
23.2     --      Consent of Coopers & Lybrand
23.3     --      Consent of Morgan, Lewis & Bockius LLP (included in its opinion filed as Exhibit 5 hereto)
24       --      Powers of Attorney (included as part of the signature page hereof)
</TABLE>



17.      UNDERTAKINGS

         The undersigned registrant hereby undertakes:

          (1) To file, during any period in which offers or sales are being
made, a post-effective amendment to this Registration Statement:

                 (i) To include any prospectus required by Section 10(a)(3) of
the Securities Act of 1933.

                 (ii) To reflect in the Prospectus any facts or events arising
after the effective date of the Registration Statement (or the most recent
post-effective amendment thereof) which, individually or in the aggregate,
represent a fundamental change in the information set forth in the Registration
Statement. Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not
exceed that which was registered) and any deviation from the low or high and of
the estimated maximum offering range may be reflected in the form of prospectus
filed with the Securities and Exchange Commission pursuant to Rule 424(b) if,
in the aggregate, the changes in volume and price represent no more than 20
percent change in the maximum aggregate offering price set forth in the
"Calculation of Registration Fee" table in the effective Registration
Statement.

                 (iii) To include any material information with respect to the
plan of distribution not previously disclosed in the Registration Statement or
any material change to such information in the Registration Statement.

provided, however, that paragraphs (1) (i) and (1) (ii) do not apply if the
information required to be included in a post-effective amendment by those
paragraphs is contained in periodic reports filed with or furnished to the
Commission by the registrant pursuant to Section 13 or 15(d) of the Securities
Exchange Act of 1934 that are incorporated by reference in the Registration
Statement.

         (2)   That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to
be a new registration statement relating to the securities offered therein, and
the offering of such securities at that time shall be deemed to be the initial
bona fide offering thereof.

         (3)  To remove from registration by means of a post-effective
amendment any of the securities being registered which remain unsold at the
termination of the offering.

         The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or 15(d) of the Securities
Exchange Act of 1934 (and, where applicable, each filing of an employee benefit
plan's annual report pursuant to Section 15(d) of the Securities Exchange Act
of 1934) that is incorporated by reference in the Registration Statement





                                      II-2

<PAGE>   18
shall be deemed to be a new registration statement relating to the securities
offered therein, and the offering of such securities at that time shall be
deemed to be the initial bona fide offering thereof.

         Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and controlling
persons of the registrant pursuant to the foregoing provisions, or otherwise,
the registrant has been advised that in the opinion of the Securities and
Exchange Commission such indemnification is against public policy as expressed
in the Securities Act of 1933 and is, therefore, unenforceable.  In the event
that a claim for indemnification against such liabilities (other than the
payment by the registrant of expenses incurred or paid by a director, officer
or controlling person of the registrant in the successful defense of any
action, suit or proceeding) is asserted by such director, officer or
controlling person in connection with the securities being registered, the
Registrant will, unless in the opinion of its counsel the matter has been
settled by controlling precedent, submit to a court of appropriate jurisdiction
the question whether such indemnification by it is against public policy as
expressed in the Securities Act of 1933 and will be governed by the final
adjudication of such issue.





                                      II-3

<PAGE>   19

                                   SIGNATURES


         Pursuant to the requirements of the Securities Act of 1933, the
registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-3 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the city of Houston, state of Texas, on December 30, 1997.


                            NATIONAL-OILWELL, INC.

                            By:      /s/  JOEL V. STAFF                        
                                     ------------------------------------------
                                     Joel V. Staff,
                                     Chairman, President and Chief Executive



                               POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, THAT EACH PERSON WHOSE SIGNATURE
APPEARS BELOW IN SO SIGNING ALSO MAKES, CONSTITUTES AND APPOINTS STEVEN W.
KRABLIN AND PAUL M. NATION, OR EITHER OF THEM, HIS TRUE AND LAWFUL
ATTORNEYS-IN-FACT AND AGENTS, WITH FULL POWER OF SUBSTITUTION AND
RESUBSTITUTION, FOR HIM AND IN HIS NAME, PLACE AND STEAD, IN ANY AND ALL
CAPACITIES, TO EXECUTE AND CAUSE TO BE FILED WITH THE SECURITIES AND EXCHANGE
COMMISSION ANY AND ALL AMENDMENTS AND POST-EFFECTIVE AMENDMENTS TO THIS
REGISTRATION STATEMENT AND A RELATED REGISTRATION STATEMENT THAT IS TO BE
EFFECTIVE UPON FILING PURSUANT TO RULE 462(b) UNDER THE SECURITIES ACT OF 1933,
AND IN EACH CASE TO FILE THE SAME, WITH ALL EXHIBITS THERETO AND OTHER
DOCUMENTS IN CONNECTION THEREWITH, AND HEREBY RATIFIES AND CONFIRMS ALL THAT
SAID ATTORNEYS-IN-FACT AND AGENTS OR THEIR SUBSTITUTE OR SUBSTITUTES MAY DO OR
CAUSE TO BE DONE BY VIRTUE HEREOF.

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed below by the following persons in the
capacities and on the date indicated.


<TABLE>
<CAPTION>
         SIGNATURE                         TITLE                                               DATE
         ---------                         -----                                               ----
<S>                                        <C>                                            <C>
/s/  JOEL V. STAFF                         Chairman of the Board of Directors             December 30, 1997
- ---------------------------------------    (Principal Executive Officer)                  
Joel V. Staff                              
                                                                                         
/s/  STEVEN W. KRABLIN                     Principal Financial and Accounting             December 30, 1997
- ---------------------------------------    Officer                                       
Steven W. Krablin                          
                                                                                         
/s/  HOWARD I. BULL                        Director                                       December 30, 1997
- ---------------------------------------                                                                    
Howard I. Bull                                                                           
                                                                                         
                                           Director                                      
- --------------------------------------- 
James C. Comis III                                                                       
                                                                                         
/s/  JAMES T. DRESHER                      Director                                       December 30, 1997
- --------------------------------------- 
James T. Dresher                                                                         
                                                                                         
                                           Director                                      
- --------------------------------------- 
W. McComb Dunwoody                                                                       
                                                                                         
/s/  WILLIAM E. MACAULAY                   Director                                       December 30, 1997
- --------------------------------------- 
William E. Macaulay
</TABLE>






                                      II-4

<PAGE>   20

<TABLE>
<S>                                        <C>                                            <C>
/s/  FREDERICK W. PHEASEY                  Director                                       December 30, 1997
- ---------------------------------------                                                                        
Frederick W. Pheasey

/s/  ROBERT L. PHILLIPS                    Director                                       December 30, 1997
- ---------------------------------------                                                                        
Robert L. Phillips

/s/  BRUCE M. ROTHSTEIN                    Director                                       December 30, 1997
- ---------------------------------------                                                                        
Bruce M. Rothstein
</TABLE>






                                      II-5

<PAGE>   21

                                 EXHIBIT INDEX



<TABLE>
<CAPTION>
EXHIBIT
NUMBER           DESCRIPTION
- ------           -----------
<S>      <C>     <C>
5        --      Opinion of Morgan, Lewis & Bockius LLP regarding legality of securities being registered
23.1     --      Consent of Ernst & Young LLP
23.2     --      Consent of Coopers & Lybrand
23.3     --      Consent of Morgan, Lewis & Bockius LLP (included in its opinion filed as Exhibit 5 hereto)
24       --      Powers of Attorney (included as part of the signature page hereof)
</TABLE>






<PAGE>   1
                                                                       EXHIBIT 5

                    [MORGAN, LEWIS & BOCKIUS LLP LETTERHEAD]



December 30, 1997

National-Oilwell, Inc.
5555 San Felipe
Houston, Texas  77056

Re:      National-Oilwell, Inc.
         Registration Statement on Form S-3

Ladies and Gentlemen:

As counsel to National-Oilwell, Inc., a Delaware corporation (the "Company"),
we have assisted in the preparation of the subject Registration Statement on
Form S-3, as amended (the "Registration Statement"), to be filed with the
Securities and Exchange Commission under the Securities Act of 1933, as amended
(the "Act"), relating to the issuance of  800,000 shares of the Company's
Common Stock, par value $0.01 per share.

In rendering the opinion set forth below, we have reviewed (a) the Registration
Statement; (b) the Company's Amended and Restated Certificate of Incorporation
and Bylaws; (c) certain records of the Company's corporate proceedings as
reflected in its minute books; and (d) such records, documents, statutes and
decisions as we have deemed relevant.  In our examination, we have assumed the
genuineness of all signatures, the authenticity of all documents submitted to
us as originals and the conformity with the original of all documents submitted
to us as copies thereof.

Our opinion set forth below is limited to
 the Delaware General Corporation Law.

Based upon the foregoing, we are of the opinion that the Shares are validly
issued, fully paid and nonassessable.

We hereby consent to the use of this opinion as Exhibit 5 to the Registration
Statement and to the reference to our firm under the heading "Legal Matters" in
the Registration Statement.  In giving such opinion, we do not thereby admit
that we are acting within the category of persons whose consent is required
under Section 7 of the Act or the rules or regulations of the Securities and
Exchange Commission thereunder.

Very truly yours,

/s/  Morgan, Lewis & Bockius LLP



<PAGE>   1
                                                                    EXHIBIT 23.1


                        CONSENT OF INDEPENDENT AUDITORS


         We consent to the reference to our firm under the caption "Experts" in
the Registration Statement (Form S-3) and related Prospectus of
National-Oilwell, Inc. for the registration of 800,000 shares of its common
stock and to the incorporation by reference therein of our report dated October
31, 1997, with respect to the consolidated financial statements of
National-Oilwell, Inc. included in its Current Report (Form 8-K) dated November
7, 1997, filed with the Securities and Exchange Commission.

                                                ERNST & YOUNG LLP


Houston, Texas
December 30, 1997





<PAGE>   1
                                                                    EXHIBIT 23.2


                        CONSENT OF INDEPENDENT AUDITORS


         We consent to the reference to our firm under the caption "Experts" in
the Registration Statement (Form S-3) and related Prospectus of
National-Oilwell, Inc. for the registration of 800,000 shares of its common
stock and to the incorporation by reference therein of our report dated
November 3, 1995, except as to Note 1 which is as of September 25, 1997, with
respect to the consolidated financial statements of National-Oilwell, Inc.,
included in its Current Report (Form 8-K) dated November 7, 1997 filed with the
Securities and Exchange Commission.


                                                Coopers & Lybrand
                                                Chartered Accountants

Edmonton, Alberta
December 30, 1997