<PAGE>   1
   As filed with the Securities and Exchange Commission on September 27, 2000
                                                     Registration No. 333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   ----------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                   ----------


                                 HYDRIL COMPANY
             (Exact name of registrant as specified in its charter)

                 DELAWARE                                    95-2777268
     (State or other jurisdiction of                     (I.R.S. Employer
      incorporation or organization)                     Identification No.)


   3300 NORTH SAM HOUSTON PARKWAY EAST                       77032-3411
             HOUSTON, TEXAS                                  (Zip Code)
(Address of Principal Executive Offices)



                                   ----------



                       HYDRIL COMPANY 2000 INCENTIVE PLAN
                   HYDRIL COMPANY EMPLOYEE STOCK PURCHASE PLAN
                            (Full title of the plans)


                                   ----------


                               MICHAEL C. KEARNEY
                   CHIEF FINANCIAL OFFICER AND VICE PRESIDENT
                                 HYDRIL COMPANY
                       3300 NORTH SAM HOUSTON PARKWAY EAST
                            HOUSTON, TEXAS 77032-3411
                     (Name and address of agent for service)

                                 (281) 449-2000
          (Telephone number, including area code, of agent for service)

                                   ----------

<TABLE>
<CAPTION>
                                                  CALCULATION OF REGISTRATION FEE
===================================================================================================================================
                                                                           PROPOSED        PROPOSED MAXIMUM
                                                     AMOUNT TO BE      MAXIMUM OFFERING   AGGREGATE OFFERING        AMOUNT OF
         TITLE OF SECURITIES TO BE REGISTERED         REGISTERED     PRICE PER SHARE (2)       PRICE (2)         REGISTRATION FEE
-----------------------------------------------------------------------------------------------------------------------------------
<S>                                                 <C>                   <C>              <C>                          <C>
Common Stock, par value $0.50 per share              2,170,000(1)          $17.00           $36,890,000                 $9,739
===================================================================================================================================

(1)      Consists of 1,950,000 shares of Common Stock reserved for issuance pursuant to the Hydril Company 2000 Incentive Plan, and
         220,000 shares of Common Stock reserved for issuance pursuant to the Hydril Company Employee Stock Purchase Plan.

(2)      Estimated pursuant to Rules 457(c) and 457(h) under the Securities Act of 1933, as amended (the "Securities Act"), solely
         for the purpose of computing the registration fee and based upon the initial public offering price per share of Common
         Stock of $17.00 as set forth in the prospectus of Hydril Company relating thereto dated September 27, 2000 as filed with
         the Securities and Exchange Commission pursuant to Rule 424(b) under the Securities Act.

===================================================================================================================================
</TABLE>



<PAGE>   2

                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS


         Note: The documents containing the information concerning the Hydril
Company 2000 Incentive Plan and the Hydril Company Employee Stock Purchase Plan,
required by Item 1 of Form S-8 and the statement of availability of registrant
information, plan information and other information required by Item 2 of Form
S-8 will be sent or given to employees as specified by Rule 428 under the
Securities Act of 1933. In accordance with Rule 428 and the requirements of Part
I of Form S-8, such documents are not being filed with the Securities and
Exchange Commission (the "Commission") either as part of this Registration
Statement or as prospectuses or prospectus supplements pursuant to Rule 424
under the Securities Act. Hydril will maintain a file of such documents in
accordance with the provisions of Rule 428. Upon request, Hydril will furnish to
the Commission or its staff a copy of any or all of the documents included in
such file.


                                       -2-

<PAGE>   3



                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT


ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents, which Hydril Company has filed with the
Commission pursuant to the Securities Act and the Securities Exchange Act of
1934, as amended (the "Exchange Act") (File No. 000-31579), are incorporated in
this registration statement by reference and shall be deemed to be a part
hereof:

                  (1) The Company's prospectus dated September 27, 2000 as filed
         with the Commission pursuant to Rule 424(b) under the Securities Act;
         and

                  (2) The description of the Company's Common Stock under the
         caption "Description of Registrant's Securities to be Registered" in
         the Company's Registration Statement on Form 8-A dated September 20,
         2000 as thereafter amended from time to time for the purpose of
         updating, changing or modifying such description.

         All documents filed by Hydril Company with the Commission pursuant to
Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act subsequent to 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 in this registration
statement by reference and to be a part hereof from the date of filing of such
documents.

         Any statement contained in this registration statement, in an amendment
hereto or in a document incorporated by reference herein shall be deemed to be
modified or superseded for purposes of this registration statement to the extent
that a statement contained herein or in any subsequently filed amendment or
supplement to this registration statement or in any document that also is
incorporated by reference herein modifies or supersedes such statement. Any
statement so modified or superseded shall not be deemed, except as so modified
or superseded, to constitute a part of this registration statement.

ITEM 4. DESCRIPTION OF SECURITIES.

         Not applicable.

ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

Delaware General Corporation Law

                  Section 145(a) of the General Corporation Law of the State of
Delaware (the "DGCL") provides that a corporation may 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 a director, officer, employee or
agent of the corporation, or is or was serving at the request of the corporation
as a director, officer, employee or agent of another corporation, partnership,
joint venture, trust or other enterprise, against 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 if
such person acted in good faith and in a manner such person 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
such person's conduct was unlawful. The termination of any action, suit or
proceeding by


                                      II-1

<PAGE>   4


judgment, order, settlement or conviction or upon a plea of nolo contendere
or its equivalent shall not, of itself, create a presumption that the person did
not act in good faith and in a manner which such person 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 reasonable cause to believe that such
person's conduct was unlawful.

                  Section 145(b) of the DGCL states that a corporation may
indemnify any person who was or is a party or is threatened to be made a party
to any threatened, pending or completed action or suit by or in the right of the
corporation to procure a judgment in its favor by reason of the fact that such
person is or was a director, officer, employee or agent of the corporation, or
is serving at the request of the corporation as a director, officer, employee or
agent of another corporation, partnership, joint venture, trust or other
enterprise against expenses (including action or suit if such person acted in
good faith and in a manner such person reasonably believed to be in or not
opposed to the best interests of the corporation and except that no
indemnification shall be made in respect of any claim issue or matter as to
which such person shall have been adjudged to be liable to the corporation
unless and only to the extent that the Court of Chancery or the court in which
such action or suit was brought shall determine upon application that, despite
the adjudication of liability but in view of all the circumstances of the case,
such person is fairly and reasonably entitled to indemnity for such expenses
that the Court of Chancery or such other court shall deem proper.

                  Section 145(c) of the DGCL provides that to the extent that a
present or former director or officer of a corporation has been successful on
the merits or otherwise in defense of any action, suit or proceeding referred to
in subsections (a) and (b) of Section 145, or in defense of any claim, issue or
matter therein, such person shall be indemnified against expenses (including
attorneys' fees) actually and reasonably incurred by such person in connection
therewith.

                  Section 145(d) of the DGCL states that any indemnification
under subsections (a) and (b) of Section 145 (unless ordered by a court) shall
be made by the corporation only as authorized in the specific case upon a
determination that indemnification of the present or former director, officer,
employee or agent is proper in the circumstances because such person has met the
applicable standard of conduct set forth in subsections (a) and (b). Such
determination shall be made, with respect to a person whose is a director or
officer at the time of such determination, (1) by the board of directors by a
majority vote of the directors who were not parties to such action, suit or
proceeding, even though less than a quorum or (2) by a committee of such
directors designated by majority vote of such directors, even though less than a
quorum or (3) if such quorum is not obtainable or, even if obtainable, a quorum
of disinterested directors so directs by independent legal counsel in a written
opinion or (4) by the stockholders.

                  Section 145(e) of the DGCL provides that expenses (including
attorneys' fees) incurred by an officer or director in defending any civil,
criminal, administrative or investigative action, suit or proceeding may be paid
by the corporation in advance of the final disposition of such action, suit or
proceeding upon receipt of an undertaking by or on behalf of such director or
officers to repay such amount if it ultimately is determined that such person is
not entitled to be indemnified by the corporation as authorized in Section 145.
Such expenses (including attorneys' fees) incurred by former directors and
officers or other employees and agents may be so paid upon such terms and
conditions, if any, as the corporation deems appropriate.

                  Section 145(f) of the DGCL states that the indemnification and
advancement of expenses provided by, or granted pursuant to, the other
subsections of Section 145 shall not be deemed exclusive of any other rights to
which those seeking indemnification or advancement of expenses may be entitled
under any bylaw, agreement, vote of stockholders or disinterested directors or
otherwise, both as to action in such person's official capacity and as to action
in another capacity while holding such office.

                  Section 145(g) of the DGCL provides that a corporation shall
have the power to purchase and maintain insurance on behalf of any person who is
or was a director, officer, employee or agent of the corporation, or is or was
serving at the request of the corporation as a director, officer, employee or
agent of another corporation, partnership, joint venture, trust or other
enterprise, against any liability asserted against such person and incurred by
such person in any such capacity, or arising out of such person's status as
such, whether or not the corporation would have the power to indemnify such
person against such liability under the provisions of Section 145.

                                      II-2


<PAGE>   5


                  Section 145(j) of the DGCL states that the indemnification and
advancement of expenses provided by, or granted pursuant to, Section 145 shall,
unless otherwise provided when authorized or ratified, continue as to a person
who has ceased to be a director, officer, employee or agent and shall inure to
the benefit of the heirs, executors and administrators of such a person.

Restated Certificate of Incorporation

                  The Restated Certificate of Incorporation of the Company
provides that a director of the Company shall not be personally liable to the
Company or its stockholders for monetary damages for breach of fiduciary duty as
a director, except for liability (i) for any breach of the director's duty of
loyalty to the Company or its stockholders, (ii) for acts or omissions not in
good faith or which involve intentional misconduct or a knowing violation of
law, (iii) under Section 174 of the DGCL, as the same exists as of the date of
the Restated Certificate of Incorporation or as such provision may be thereafter
amended, supplemented or replaced or (iv) for any transaction from which the
director derived an improper personal benefit. If the DGCL is amended after the
filing of the Restated Certificate of Incorporation to authorize the further
elimination or limitation of the personal liability of directors, then the
liability of a director of the Company, in addition to the limitation on
personal liability described above, shall be limited to the fullest extent
permitted by the amended DGCL. Further, any repeal or modification of such
provision of the Restated Certificate of Incorporation by the stockholders of
the Company shall be prospective only, and shall not adversely affect any
limitation on the personal liability of a director of the Company existing at
the time of such repeal or modification.

Bylaws

                  The Bylaws of the Company provide that each person who at any
time shall serve or shall have served as a director, officer, employee or agent
of the Company, or any person who, while a director, officer, employee or agent
of the Company, is or was serving at the written request of the Company (in
accordance with written procedures adopted from time to time by the Board of
Directors) as a director, officer, partner, venturer, proprietor, trustee,
employee, agent or similar functionary of another foreign or domestic
corporation, partnership, joint venture, sole proprietorship, trust, employee
benefit plan or other enterprise, shall be entitled to indemnification and the
advancement of expenses incurred by such person from the Company as, and to the
fullest extent, permitted by Section 145 of the DGCL or any successor statutory
provision, as from time to time amended. The Bylaws provide that this right to
indemnification and the advancement of expenses is not deemed exclusive of any
other rights to which those to be indemnified may be entitled as a matter of law
or under any agreement, vote of stockholders or disinterested directors of the
Company, or other arrangement.

Indemnification Agreements

                  The Company has entered into Indemnification Agreements with
each of its directors and executive officers. The Indemnification Agreements
provide that the Company shall indemnify the director or officer and hold him
harmless from any losses and expenses which, in type or amount, are not insured
under the directors and officers' liability insurance maintained by the Company,
and generally indemnify the director or officer against losses and expenses as a
result of a claim or claims made against him for any breach of duty, neglect,
error, misstatement, misleading statement, omission or other act done or
wrongfully attempted by the director or officer or any of the foregoing alleged
by any claimant or any claim against the director or officer solely by reason of
him being a director or officer of the Company, subject to certain exclusions.
The Indemnification Agreements also provide certain procedures regarding the
right to indemnification and the advancement of expenses.

Underwriting Agreement

                  The Underwriting Agreement entered into by the Company in
connection with its initial public offering provides for the indemnification of
the directors and officers of the Company in certain circumstances.


                                      II-3


<PAGE>   6


Insurance

                  The Company has obtained a policy of liability insurance to
insure its officers and directors against losses resulting from certain acts
committed by them in their capacities as officers and directors of the Company.

ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

         Not Applicable.

ITEM 8. EXHIBITS.

Exhibit
Number                              Document Description

  4.1       --       Form of Restated Certificate of Incorporation (incorporated
                     by reference to Exhibit 3.1 of the registration statement
                     of Hydril Company on Form S-1, Registration No. 333-38954).

  4.2       --       Restated Bylaws of the Company (incorporated by reference
                     to Exhibit 3.2 of the registration statement of Hydril
                     Company on Form S-1, Registration No. 333-38954).

  4.3       --       Form of Specimen Common Stock Certificate (incorporated by
                     reference to Exhibit 4.1 of the registration statement of
                     Hydril Company on Form S-1, Registration No. 333-38954).

  4.4       --       Registration Rights Agreement among the Company and the
                     stockholders named therein (incorporated by reference to
                     Exhibit 4.2 of the registration statement of Hydril Company
                     on Form S-1, Registration No. 333-38954).

  4.5       --       Hydril Company 2000 Incentive Plan (incorporated by
                     reference to Exhibit 10.3 of the registration statement of
                     Hydril Company on Form S-1, Registration No. 333-38954).

  4.6       --       Hydril Company Employee Stock Purchase Plan (incorporated
                     by reference to Exhibit 10.6 of the registration statement
                     of Hydril Company on Form S-1, Registration No. 333-38954).

 *4.7       --       Form of First Amendment to the Hydril Company Employee
                     Stock Purchase Plan.

 *5.1       --       Opinion of Baker Botts L.L.P.

*23.1       --       Consent of Deloitte & Touche LLP.

*23.2       --       Consent of Baker Botts L.L.P. (included in Exhibit 5.1).

*24.1       --       Powers of Attorney.

----------

*        Filed herewith.


ITEM 9. UNDERTAKINGS.

         (a) 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:


                                      II-4

<PAGE>   7

                           (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 end 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) of the Securities Act of
                  1933 if, in the aggregate, the changes in volume and price
                  represent no more than a 20% 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 (a)(1)(i) and (a)(1)(ii) do not
         apply if the registration statement is on Form S-3 or Form S-8, and the
         information required to be included in a post-effective amendment by
         those paragraphs is contained in periodic reports filed by the
         registrant pursuant to section 13 or section 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.

         (b) 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 section 15(d) of the
Securities Exchange Act of 1934 that is incorporated by reference in the
registration statement 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.

         (c) 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 Act 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 Act and will
be governed by the final adjudication of such issue.


                                      II-5


<PAGE>   8

                                   SIGNATURES

                  Pursuant to the requirements of the Securities Act of 1933, as
amended, the Registrant 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 the 27th day of September, 2000.

                            HYDRIL COMPANY


                            By: /s/ CHRISTOPHER T. SEAVER
                               ------------------------------------------------
                               Christopher T. Seaver
                               President, Chief Executive Officer and  Director


                  Pursuant to the requirements of the Securities Act of 1933, as
amended, this to Registration Statement has been signed below by the following
persons in the capacities indicated on the 27th day of September, 2000.

<TABLE>
<CAPTION>
                  SIGNATURE                                                    TITLE
<S>                                                     <C>
      /s/ CHRISTOPHER T. SEAVER                          President, Chief Executive Officer and Director (Principal
---------------------------------------------------      Executive Officer)
         Christopher T. Seaver


                 *                                       Chief Financial Officer  and Vice President -
---------------------------------------------------      Administration (Principal Financial and Accounting
         Michael C. Kearney                              Officer)


                 *                                       Chairman of the Board
---------------------------------------------------
         Richard C. Seaver


                 *                                       Director
---------------------------------------------------
         Richard A. Archer


                 *                                       Director
---------------------------------------------------
         Jerry S. Cox


                 *                                       Director
---------------------------------------------------
         Gordon B. Crary, Jr.


                 *                                       Director
---------------------------------------------------
         Patrick T. Seaver


                 *                                       Director
---------------------------------------------------
         T. Donald Stacy


                 *                                       Director
---------------------------------------------------
         Lew O. Ward


     /s/ CHRISTOPHER T. SEAVER
----------------------------------------------------
         Name: Christopher T. Seaver
         Attorney-in-fact
</TABLE>





<PAGE>   9


                                  EXHIBIT INDEX


<TABLE>
<CAPTION>
EXHIBIT NO.                        DESCRIPTION
-----------                        -----------
<S>                 <C>
  4.1       --       Form of Restated Certificate of Incorporation (incorporated
                     by reference to Exhibit 3.1 of the registration statement
                     of Hydril Company on Form S-1, Registration No. 333-38954).

  4.2       --       Restated Bylaws of the Company (incorporated by reference
                     to Exhibit 3.2 of the registration statement of Hydril
                     Company on Form S-1, Registration No. 333-38954).

  4.3       --       Form of Specimen Common Stock Certificate (incorporated by
                     reference to Exhibit 4.1 of the registration statement of
                     Hydril Company on Form S-1, Registration No. 333-38954).

  4.4       --       Registration Rights Agreement among the Company and the
                     stockholders named therein (incorporated by reference to
                     Exhibit 4.2 of the registration statement of Hydril Company
                     on Form S-1, Registration No. 333-38954).

  4.5       --       Hydril Company 2000 Incentive Plan (incorporated by
                     reference to Exhibit 10.3 of the registration statement of
                     Hydril Company on Form S-1, Registration No. 333-38954).

  4.6       --       Hydril Company Employee Stock Purchase Plan (incorporated
                     by reference to Exhibit 10.6 of the registration statement
                     of Hydril Company on Form S-1, Registration No. 333-38954).

 *4.7       --       Form of First Amendment to the Hydril Company Employee
                     Stock Purchase Plan.

 *5.1       --       Opinion of Baker Botts L.L.P.

*23.1       --       Consent of Deloitte & Touche LLP.

*23.2       --       Consent of Baker Botts L.L.P. (included in Exhibit 5.1).

*24.1       --       Powers of Attorney.
</TABLE>


----------

*        Filed herewith.
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1
   As filed with the Securities and Exchange Commission on September 27, 2000
                                                     Registration No. 333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   ----------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                   ----------

                                 HYDRIL COMPANY
             (Exact name of registrant as specified in its charter)

                 DELAWARE                                    95-2777268
     (State or other jurisdiction of                     (I.R.S. Employer
      incorporation or organization)                     Identification No.)

   3300 NORTH SAM HOUSTON PARKWAY EAST                       77032-3411
             HOUSTON, TEXAS                                  (Zip Code)
(Address of Principal Executive Offices)

                                   ----------

                       HYDRIL COMPANY 2000 INCENTIVE PLAN
                   HYDRIL COMPANY EMPLOYEE STOCK PURCHASE PLAN
                            (Full title of the plans)

                                   ----------

                               MICHAEL C. KEARNEY
                   CHIEF FINANCIAL OFFICER AND VICE PRESIDENT
                                 HYDRIL COMPANY
                       3300 NORTH SAM HOUSTON PARKWAY EAST
                            HOUSTON, TEXAS 77032-3411
                     (Name and address of agent for service)

                                 (281) 449-2000
          (Telephone number, including area code, of agent for service)

                                   ----------
CALCULATION OF REGISTRATION FEE
===================================================================================================================================
                                                                           PROPOSED        PROPOSED MAXIMUM
                                                     AMOUNT TO BE      MAXIMUM OFFERING   AGGREGATE OFFERING        AMOUNT OF
         TITLE OF SECURITIES TO BE REGISTERED         REGISTERED     PRICE PER SHARE (2)       PRICE (2)         REGISTRATION FEE
-----------------------------------------------------------------------------------------------------------------------------------
Common Stock, par value $0.50 per share              2,170,000(1)          $17.00           $36,890,000                 $9,739
===================================================================================================================================

(1)      Consists of 1,950,000 shares of Common Stock reserved for issuance pursuant to the Hydril Company 2000 Incentive Plan, and
         220,000 shares of Common Stock reserved for issuance pursuant to the Hydril Company Employee Stock Purchase Plan.

(2)      Estimated pursuant to Rules 457(c) and 457(h) under the Securities Act of 1933, as amended (the "Securities Act"), solely
         for the purpose of computing the registration fee and based upon the initial public offering price per share of Common
         Stock of $17.00 as set forth in the prospectus of Hydril Company relating thereto dated September 27, 2000 as filed with
         the Securities and Exchange Commission pursuant to Rule 424(b) under the Securities Act.

===================================================================================================================================
2

                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

         Note: The documents containing the information concerning the Hydril
Company 2000 Incentive Plan and the Hydril Company Employee Stock Purchase Plan,
required by Item 1 of Form S-8 and the statement of availability of registrant
information, plan information and other information required by Item 2 of Form
S-8 will be sent or given to employees as specified by Rule 428 under the
Securities Act of 1933. In accordance with Rule 428 and the requirements of Part
I of Form S-8, such documents are not being filed with the Securities and
Exchange Commission (the "Commission") either as part of this Registration
Statement or as prospectuses or prospectus supplements pursuant to Rule 424
under the Securities Act. Hydril will maintain a file of such documents in
accordance with the provisions of Rule 428. Upon request, Hydril will furnish to
the Commission or its staff a copy of any or all of the documents included in
such file.

                                       -2-
3

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents, which Hydril Company has filed with the
Commission pursuant to the Securities Act and the Securities Exchange Act of
1934, as amended (the "Exchange Act") (File No. 000-31579), are incorporated in
this registration statement by reference and shall be deemed to be a part
hereof:

                  (1) The Company's prospectus dated September 27, 2000 as filed
         with the Commission pursuant to Rule 424(b) under the Securities Act;
         and

                  (2) The description of the Company's Common Stock under the
         caption "Description of Registrant's Securities to be Registered" in
         the Company's Registration Statement on Form 8-A dated September 20,
         2000 as thereafter amended from time to time for the purpose of
         updating, changing or modifying such description.

         All documents filed by Hydril Company with the Commission pursuant to
Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act subsequent to 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 in this registration
statement by reference and to be a part hereof from the date of filing of such
documents.

         Any statement contained in this registration statement, in an amendment
hereto or in a document incorporated by reference herein shall be deemed to be
modified or superseded for purposes of this registration statement to the extent
that a statement contained herein or in any subsequently filed amendment or
supplement to this registration statement or in any document that also is
incorporated by reference herein modifies or supersedes such statement. Any
statement so modified or superseded shall not be deemed, except as so modified
or superseded, to constitute a part of this registration statement.

ITEM 4. DESCRIPTION OF SECURITIES.

         Not applicable.

ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

Delaware General Corporation Law

                  Section 145(a) of the General Corporation Law of the State of
Delaware (the "DGCL") provides that a corporation may 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 a director, officer, employee or
agent of the corporation, or is or was serving at the request of the corporation
as a director, officer, employee or agent of another corporation, partnership,
joint venture, trust or other enterprise, against 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 if
such person acted in good faith and in a manner such person 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
such person's conduct was unlawful. The termination of any action, suit or
proceeding by

                                      II-1
4

judgment, order, settlement or conviction or upon a plea of nolo contendere
or its equivalent shall not, of itself, create a presumption that the person did
not act in good faith and in a manner which such person 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 reasonable cause to believe that such
person's conduct was unlawful.

                  Section 145(b) of the DGCL states that a corporation may
indemnify any person who was or is a party or is threatened to be made a party
to any threatened, pending or completed action or suit by or in the right of the
corporation to procure a judgment in its favor by reason of the fact that such
person is or was a director, officer, employee or agent of the corporation, or
is serving at the request of the corporation as a director, officer, employee or
agent of another corporation, partnership, joint venture, trust or other
enterprise against expenses (including action or suit if such person acted in
good faith and in a manner such person reasonably believed to be in or not
opposed to the best interests of the corporation and except that no
indemnification shall be made in respect of any claim issue or matter as to
which such person shall have been adjudged to be liable to the corporation
unless and only to the extent that the Court of Chancery or the court in which
such action or suit was brought shall determine upon application that, despite
the adjudication of liability but in view of all the circumstances of the case,
such person is fairly and reasonably entitled to indemnity for such expenses
that the Court of Chancery or such other court shall deem proper.

                  Section 145(c) of the DGCL provides that to the extent that a
present or former director or officer of a corporation has been successful on
the merits or otherwise in defense of any action, suit or proceeding referred to
in subsections (a) and (b) of Section 145, or in defense of any claim, issue or
matter therein, such person shall be indemnified against expenses (including
attorneys' fees) actually and reasonably incurred by such person in connection
therewith.

                  Section 145(d) of the DGCL states that any indemnification
under subsections (a) and (b) of Section 145 (unless ordered by a court) shall
be made by the corporation only as authorized in the specific case upon a
determination that indemnification of the present or former director, officer,
employee or agent is proper in the circumstances because such person has met the
applicable standard of conduct set forth in subsections (a) and (b). Such
determination shall be made, with respect to a person whose is a director or
officer at the time of such determination, (1) by the board of directors by a
majority vote of the directors who were not parties to such action, suit or
proceeding, even though less than a quorum or (2) by a committee of such
directors designated by majority vote of such directors, even though less than a
quorum or (3) if such quorum is not obtainable or, even if obtainable, a quorum
of disinterested directors so directs by independent legal counsel in a written
opinion or (4) by the stockholders.

                  Section 145(e) of the DGCL provides that expenses (including
attorneys' fees) incurred by an officer or director in defending any civil,
criminal, administrative or investigative action, suit or proceeding may be paid
by the corporation in advance of the final disposition of such action, suit or
proceeding upon receipt of an undertaking by or on behalf of such director or
officers to repay such amount if it ultimately is determined that such person is
not entitled to be indemnified by the corporation as authorized in Section 145.
Such expenses (including attorneys' fees) incurred by former directors and
officers or other employees and agents may be so paid upon such terms and
conditions, if any, as the corporation deems appropriate.

                  Section 145(f) of the DGCL states that the indemnification and
advancement of expenses provided by, or granted pursuant to, the other
subsections of Section 145 shall not be deemed exclusive of any other rights to
which those seeking indemnification or advancement of expenses may be entitled
under any bylaw, agreement, vote of stockholders or disinterested directors or
otherwise, both as to action in such person's official capacity and as to action
in another capacity while holding such office.

                  Section 145(g) of the DGCL provides that a corporation shall
have the power to purchase and maintain insurance on behalf of any person who is
or was a director, officer, employee or agent of the corporation, or is or was
serving at the request of the corporation as a director, officer, employee or
agent of another corporation, partnership, joint venture, trust or other
enterprise, against any liability asserted against such person and incurred by
such person in any such capacity, or arising out of such person's status as
such, whether or not the corporation would have the power to indemnify such
person against such liability under the provisions of Section 145.

                                      II-2
5

                  Section 145(j) of the DGCL states that the indemnification and
advancement of expenses provided by, or granted pursuant to, Section 145 shall,
unless otherwise provided when authorized or ratified, continue as to a person
who has ceased to be a director, officer, employee or agent and shall inure to
the benefit of the heirs, executors and administrators of such a person.

Restated Certificate of Incorporation

                  The Restated Certificate of Incorporation of the Company
provides that a director of the Company shall not be personally liable to the
Company or its stockholders for monetary damages for breach of fiduciary duty as
a director, except for liability (i) for any breach of the director's duty of
loyalty to the Company or its stockholders, (ii) for acts or omissions not in
good faith or which involve intentional misconduct or a knowing violation of
law, (iii) under Section 174 of the DGCL, as the same exists as of the date of
the Restated Certificate of Incorporation or as such provision may be thereafter
amended, supplemented or replaced or (iv) for any transaction from which the
director derived an improper personal benefit. If the DGCL is amended after the
filing of the Restated Certificate of Incorporation to authorize the further
elimination or limitation of the personal liability of directors, then the
liability of a director of the Company, in addition to the limitation on
personal liability described above, shall be limited to the fullest extent
permitted by the amended DGCL. Further, any repeal or modification of such
provision of the Restated Certificate of Incorporation by the stockholders of
the Company shall be prospective only, and shall not adversely affect any
limitation on the personal liability of a director of the Company existing at
the time of such repeal or modification.

Bylaws

                  The Bylaws of the Company provide that each person who at any
time shall serve or shall have served as a director, officer, employee or agent
of the Company, or any person who, while a director, officer, employee or agent
of the Company, is or was serving at the written request of the Company (in
accordance with written procedures adopted from time to time by the Board of
Directors) as a director, officer, partner, venturer, proprietor, trustee,
employee, agent or similar functionary of another foreign or domestic
corporation, partnership, joint venture, sole proprietorship, trust, employee
benefit plan or other enterprise, shall be entitled to indemnification and the
advancement of expenses incurred by such person from the Company as, and to the
fullest extent, permitted by Section 145 of the DGCL or any successor statutory
provision, as from time to time amended. The Bylaws provide that this right to
indemnification and the advancement of expenses is not deemed exclusive of any
other rights to which those to be indemnified may be entitled as a matter of law
or under any agreement, vote of stockholders or disinterested directors of the
Company, or other arrangement.

Indemnification Agreements

                  The Company has entered into Indemnification Agreements with
each of its directors and executive officers. The Indemnification Agreements
provide that the Company shall indemnify the director or officer and hold him
harmless from any losses and expenses which, in type or amount, are not insured
under the directors and officers' liability insurance maintained by the Company,
and generally indemnify the director or officer against losses and expenses as a
result of a claim or claims made against him for any breach of duty, neglect,
error, misstatement, misleading statement, omission or other act done or
wrongfully attempted by the director or officer or any of the foregoing alleged
by any claimant or any claim against the director or officer solely by reason of
him being a director or officer of the Company, subject to certain exclusions.
The Indemnification Agreements also provide certain procedures regarding the
right to indemnification and the advancement of expenses.

Underwriting Agreement

                  The Underwriting Agreement entered into by the Company in
connection with its initial public offering provides for the indemnification of
the directors and officers of the Company in certain circumstances.

                                      II-3
6

Insurance

                  The Company has obtained a policy of liability insurance to
insure its officers and directors against losses resulting from certain acts
committed by them in their capacities as officers and directors of the Company.

ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

         Not Applicable.

ITEM 8. EXHIBITS.

Exhibit
Number                              Document Description

  4.1       --       Form of Restated Certificate of Incorporation (incorporated
                     by reference to Exhibit 3.1 of the registration statement
                     of Hydril Company on Form S-1, Registration No. 333-38954).

  4.2       --       Restated Bylaws of the Company (incorporated by reference
                     to Exhibit 3.2 of the registration statement of Hydril
                     Company on Form S-1, Registration No. 333-38954).

  4.3       --       Form of Specimen Common Stock Certificate (incorporated by
                     reference to Exhibit 4.1 of the registration statement of
                     Hydril Company on Form S-1, Registration No. 333-38954).

  4.4       --       Registration Rights Agreement among the Company and the
                     stockholders named therein (incorporated by reference to
                     Exhibit 4.2 of the registration statement of Hydril Company
                     on Form S-1, Registration No. 333-38954).

  4.5       --       Hydril Company 2000 Incentive Plan (incorporated by
                     reference to Exhibit 10.3 of the registration statement of
                     Hydril Company on Form S-1, Registration No. 333-38954).

  4.6       --       Hydril Company Employee Stock Purchase Plan (incorporated
                     by reference to Exhibit 10.6 of the registration statement
                     of Hydril Company on Form S-1, Registration No. 333-38954).

 *4.7       --       Form of First Amendment to the Hydril Company Employee
                     Stock Purchase Plan.

 *5.1       --       Opinion of Baker Botts L.L.P.

*23.1       --       Consent of Deloitte & Touche LLP.

*23.2       --       Consent of Baker Botts L.L.P. (included in Exhibit 5.1).

*24.1       --       Powers of Attorney.

----------

*        Filed herewith.

ITEM 9. UNDERTAKINGS.

         (a) 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:

                                      II-4
7

                           (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 end 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) of the Securities Act of
                  1933 if, in the aggregate, the changes in volume and price
                  represent no more than a 20% 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 (a)(1)(i) and (a)(1)(ii) do not
         apply if the registration statement is on Form S-3 or Form S-8, and the
         information required to be included in a post-effective amendment by
         those paragraphs is contained in periodic reports filed by the
         registrant pursuant to section 13 or section 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.

         (b) 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 section 15(d) of the
Securities Exchange Act of 1934 that is incorporated by reference in the
registration statement 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.

         (c) 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 Act 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 Act and will
be governed by the final adjudication of such issue.

                                      II-5
8

                                   SIGNATURES

                  Pursuant to the requirements of the Securities Act of 1933, as
amended, the Registrant 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 the 27th day of September, 2000.

                            HYDRIL COMPANY

                            By: /s/ CHRISTOPHER T. SEAVER
                               ------------------------------------------------
                               Christopher T. Seaver
                               President, Chief Executive Officer and  Director

                  Pursuant to the requirements of the Securities Act of 1933, as
amended, this to Registration Statement has been signed below by the following
persons in the capacities indicated on the 27th day of September, 2000.
SIGNATURE                                                    TITLE
/s/ CHRISTOPHER T. SEAVER                          President, Chief Executive Officer and Director (Principal
---------------------------------------------------      Executive Officer)
         Christopher T. Seaver

                 *                                       Chief Financial Officer  and Vice President -
---------------------------------------------------      Administration (Principal Financial and Accounting
         Michael C. Kearney                              Officer)

                 *                                       Chairman of the Board
---------------------------------------------------
         Richard C. Seaver

                 *                                       Director
---------------------------------------------------
         Richard A. Archer

                 *                                       Director
---------------------------------------------------
         Jerry S. Cox

                 *                                       Director
---------------------------------------------------
         Gordon B. Crary, Jr.

                 *                                       Director
---------------------------------------------------
         Patrick T. Seaver

                 *                                       Director
---------------------------------------------------
         T. Donald Stacy

                 *                                       Director
---------------------------------------------------
         Lew O. Ward

     /s/ CHRISTOPHER T. SEAVER
----------------------------------------------------
         Name: Christopher T. Seaver
         Attorney-in-fact
9

                                  EXHIBIT INDEX
EXHIBIT NO.                        DESCRIPTION
-----------                        -----------
4.1       --       Form of Restated Certificate of Incorporation (incorporated
                     by reference to Exhibit 3.1 of the registration statement
                     of Hydril Company on Form S-1, Registration No. 333-38954).

  4.2       --       Restated Bylaws of the Company (incorporated by reference
                     to Exhibit 3.2 of the registration statement of Hydril
                     Company on Form S-1, Registration No. 333-38954).

  4.3       --       Form of Specimen Common Stock Certificate (incorporated by
                     reference to Exhibit 4.1 of the registration statement of
                     Hydril Company on Form S-1, Registration No. 333-38954).

  4.4       --       Registration Rights Agreement among the Company and the
                     stockholders named therein (incorporated by reference to
                     Exhibit 4.2 of the registration statement of Hydril Company
                     on Form S-1, Registration No. 333-38954).

  4.5       --       Hydril Company 2000 Incentive Plan (incorporated by
                     reference to Exhibit 10.3 of the registration statement of
                     Hydril Company on Form S-1, Registration No. 333-38954).

  4.6       --       Hydril Company Employee Stock Purchase Plan (incorporated
                     by reference to Exhibit 10.6 of the registration statement
                     of Hydril Company on Form S-1, Registration No. 333-38954).

 *4.7       --       Form of First Amendment to the Hydril Company Employee
                     Stock Purchase Plan.

 *5.1       --       Opinion of Baker Botts L.L.P.

*23.1       --       Consent of Deloitte & Touche LLP.

*23.2       --       Consent of Baker Botts L.L.P. (included in Exhibit 5.1).

*24.1       --       Powers of Attorney.
----------

*        Filed herewith.