<PAGE>
                                                                     Exhibit 3.1

                               STATE of DELAWARE
                           CERTIFICATE of AMENDMENT of
                          CERTIFICATE of INCORPORATION

     First:  That at a  meeting  of the  Board of  Directors  of  Maverick  Tube
Corporation, resolutions were duly adopted setting forth a proposed amendment of
the Certificate of Incorporation of said  corporation,  declaring said amendment
to be  advisable  and  recommending  that  the  amendment  be  proposed  to  the
stockholders  for approval at the Annual Meeting.  The resolution  setting forth
the proposed amendment is as follows:

     RESOLVED,  that the Board hereby approves,  adopts and declares advisable a
proposal  to amend  Article  Fourth of the  Certificate  of  Incorporation  (the
"Amendment  Proposal")  to increase  the  authorized  number of shares of Common
Stock from twenty million to forty million,  such Article Fourth, as amended, to
read in its entirety as follows:

     "FOURTH.  The total number of shares of stock which the  Corporation  shall
     have  the  authority  to issue  is  45,000,000  shares  of  Capital  Stock,
     consisting of 5,000,000 shares of preferred stock, par value $.01 per share
     (the "Preferred  Stock"),  and 40,000,000 shares of Common Stock, par value
     $.01 per share (the "Common Stock")."

     Second: That thereafter,  pursuant to resolution of its Board of Directors,
the amendment was proposed to the  stockholders  at a meeting of the stockholder
of said corporation duly called and held, upon notice in accordance with Section
222 of the General Corporation Law of the State of Delaware at which meeting the
necessary  number of share as  required  by  statute  were voted in favor of the
amendment.

     Third:  That  said  amendment  was  duly  adopted  in  accordance  with the
provisions  of  Section  242 of the  General  Corporation  Law of the  State  of
Delaware and of said corporation's certificate of incorporation and by-laws.

     Fourth:  That the capital of said corporation shall not be reduced under or
by reason of said amendment.

     In  Witness  Whereof,  said  Maverick  Tube  Corporation  has  caused  this
certificate to be signed by Pamela G. Boone, an Authorized Officer, this 1st day
of September, 1998.

                                                     By:  /s/ Pamela G. Boone
                                                        ------------------------
                                                        Pamela G. Boone
<PAGE>
                              AMENDED AND RESTATED
                          CERTIFICATE OF INCORPORATION

                                       OF

                           MAVERICK TUBE CORPORATION


     The name under which the  Corporation was  incorporated  originally was MAV
Holding  Company.  The  original  Certificate  of  Incorporation  of MAV Holding
Company  was filed with the  Secretary  of State of the State of Delaware on May
26, 1987. This Amended and Restated  Certificate of Incorporation  has been duly
adopted in  accordance  with Section 245 of the General  Corporation  Law of the
State of Delaware.

     FIRST: The name of the Corporation is:

                        MAVERICK TUBE CORPORATION

     SECOND:  The address of its  registered  office in the State of Delaware is
1209 Orange Street, in the City of Wilmington, County of New Castle. The name of
its registered agent at such address is The Corporation Trust Company.

     THIRD:  The nature of the  business or purposes to be conducted or promoted
is to  engage in any  lawful  act or  activity  for  which  corporations  may be
organized under the General Corporation Law of the State of Delaware.

     FOURTH:  The total  number of shares of stock which the  Corporation  shall
have the authority to issue is 25,000,000 shares of capital stock, consisting of
5,000,000  shares of preferred  stock,  par value $.01 per share (the "Preferred
Stock"),  and 20,000,000  shares of common stock,  par value $.01 per share (the
"Common Stock").

     The designations, powers, preferences and relative, participating, optional
or other special rights and  qualifications,  limitations or restrictions of the
Preferred  Stock shall be  established  by  resolution of the Board of Directors
pursuant to Section 151 of the General Corporation Law of the State of Delaware.

     FIFTH: The Corporation is to have a perpetual existence.

     SIXTH:  In  furtherance  and not in limitation  of the powers  conferred by
statute, the Board of Directors is expressly authorized to make, alter or repeal
the bylaws of the Corporation.

     SEVENTH:  Election of directors  need not be by written  ballot  unless the
bylaws of the Corporation shall so provide.

     EIGHTH: No action shall be taken by the stockholders except at an annual or
special meeting of stockholders and stockholders may not act by written consent.

     NINTH:  Special  meetings of the  stockholder  of the  Corporation  for any
purpose or purposes may be called at any time by the Board of Directors, or by a
committee of the Board of Directors  which has been duly designated by the Board
of Directors and whose powers and authority,  as provided in a resolution of the
Board of  Directors  or in the bylaws of the  Corporation,  include the power to
call such meetings.  Special  meetings of stockholder of the Corporation may not
be called by any other person or persons.

     TENTH: No director of this  Corporation  shall be personally  liable to the
Corporation  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  Corporation  or its  stockholders,  (ii)  for  acts or
omissions not in good faith or which involve intentional misconduct or a knowing
violation of the law, (iii) under Section 174 of the General  Corporation Law of
the State of  Delaware,  or (iv) for any  transaction  from  which the  director
derived an improper personal benefit.

     If the  General  Corporation  Law of the  State of  Delaware  is  hereafter
amended to  authorize  corporate  action  further  limiting or  eliminating  the
personal  liability  of  directors,  then the  liability  of the director to the
Corporation  shall be limited or eliminated to the fullest  extent  permitted by
the General Corporation Law of the State of Delaware, as so amended from time to
time. Any repeal or modification of this Article shall be prospective  only, and
shall not  adversely  affect  any  limitation  on the  personal  liability  of a
director of the Corporation existing at the time of such repeal or modification.

     ELEVENTH: The Corporation shall, to the fullest extent permitted by Section
145 of the General  Corporation  Law of the State of  Delaware,  as amended from
time to time,  indemnify  all persons whom it may  indemnify  pursuant  thereto.
Expenses  (including  attorneys' fees) incurred by an officer or director of the
Corporation  or any of its  direct  or  indirect  wholly-owned  subsidiaries  in
defending any civil,  criminal,  administrative or investigative action, suit or
proceeding shall 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 officer to repay such amount if it shall  ultimately
be determined  that he is not entitled to be indemnified  by the  Corporation as
authorized  above.  Such expenses  (including  attorney' fees) incurred by other
employees  and agents may be so paid upon such terms and  condition,  if any, as
the Board of Directors deems appropriate.

     The  indemnification  and  advancement of expenses  provided by, or granted
pursuant to, this Article  shall not be deemed  exclusive of any other rights to
which those seeking  indemnification  or advancement of expenses may be entitled
under any provision of law, the certificate of  incorporation or bylaws or other
governing  documents of any direct or indirect  wholly-owned  subsidiary  of the
Corporation,  or any agreement,  vote of stockholders or disinterested directors
or  otherwise,  both as to action in his  official  capacity and as to action in
another  capacity  while  holding  any of the  positions  or  having  any of the
relationships referred to in this Article.

     TWELFTH:  The number of  directors  shall be fixed from time to time by the
bylaws of he  Corporation  or an amendment  thereof duly adopted by the Board of
Directors  or by  the  stockholders  acting  in  the  manner  now  or  hereafter
prescribed by statute.

     Notwithstanding  any of the  foregoing  provisions  of this  Article,  each
director  shall serve until his  successor is elected and qualified or until his
death, retirement, resignation or removal. No director may be removed during his
term except for cause.

     THIRTEENTH:  The  provisions  set forth in this Article  THIRTEENTH  and in
Articles EIGHTH (dealing with action taken by stockholders), NINTH (dealing with
the calling of special meetings of stockholders),  TENTH (dealing with liability
of  directors)  and ELEVENTH  (dealing with  indemnification)  herein may not be
repealed or amended in any respect, and no Article imposing cumulative voting in
the election of directors may be added to this Amended and Restated  Certificate
of  Incorporation or to the bylaws of the Corporation or to any amendment hereof
or thereof,  unless such action is approved by the affirmative  vote of not less
than 75% of the total  voting  power of all  shares of stock in the  Corporation
entitled to vote in the election of directors,  considered  for purposes of this
Article  THIRTEENTH  as one class.  The voting  requirements  contained  in this
Article  THIRTEENTH shall be in addition to the voting  requirements  imposed by
law, other provisions of this Amended and Restated  Certificate of Incorporation
or any  Certificate of Designation of Preferences in favor of certain classes or
series of classes of shares of the Corporation.

     FOURTEENTH:  The Corporation  reserves the right to amend, alter, change or
repeal any  provisions  contained in this Amended and  Restated  Certificate  of
Incorporation,  in the manner now or  hereafter  prescribed  by statue,  and all
rights   conferred  upon   stockholder   herein  are  granted  subject  to  this
reservation. Notwithstanding the foregoing, the provisions set forth in Articles
EIGHTH,  NINTH, TENTH, ELEVENTH and THIRTEENTH may not be repealed or amended in
any respect  unless such repeal or amendment is approved as specified in Article
THIRTEENTH herein.

     IN WITNESS  WHEREOF,  Maverick Tube Corporation has caused this Amended and
Restated  Certificate of Incorporation  to be executed by Dan P. Boxdorfer,  its
Vice President, and attested by Charles Struckhoff, its Secretary, this 18th day
of March, 1991.

                                   MAVERICK TUBE CORPORATION

                                   By:     /s/  Dan P. Boxdorfer
                                       ------------------------------------
                                       Dan P. Boxdorfer, Vice President


[Seal]

ATTEST:

By:     /s/  Charles Struckoff
    --------------------------------
    Charles Struckoff, Secretary


                                )
                                )   SS:
                                )

I, Ali  Radtke,  a Notary  Public,  do hereby  certify  that on this 18th day of
March,  1991,  personally  appeared  before me Dan P Boxdorfer,  who being by me
first duly  sworn,  declared  that he is the Vice  President  of  Maverick  Tube
Corporation,  that he signed the  foregoing  document as Vice  President  of the
Corporation, and that the statements therein contained are true.


                                   /s/  Ali Radtke
                                   -----------------
                                   Notary Public