**Exhibit
      3.1**





**RESTATED
      CERTIFICATE OF INCORPORATION**





**OF**





**INSITUFORM
      TECHNOLOGIES, INC.**





INSITUFORM
      TECHNOLOGIES, INC., a corporation organized and existing by virtue of the
      General Corporation Law of Delaware (the “Corporation”), pursuant to the General
      Corporation Law of Delaware does hereby certify as follows:





FIRST:
      (a) The present name of the Corporation is INSITUFORM TECHNOLOGIES,
      INC.




(b)
      The name under which the Corporation was originally incorporated is INSITUFORM
      OF NORTH AMERICA, INC.; and the date of filing the original certificate of
      incorporation with the Secretary of State of the State of Delaware is March
      27,
      1980.





SECOND:
      The provisions of the certificate of incorporation of the Corporation, as
      heretofore amended and/or supplemented, are hereby restated and integrated
      into
      the single instrument which is hereinafter set forth, and which is entitled
      Restated Certificate of Incorporation of Insituform Technologies, Inc., without
      further amendment and without any discrepancy between the provisions of the
      certificate of incorporation, as heretofore amended and supplemented, and the
      provisions of the said single instrument hereinafter set forth.





THIRD:
      The Board of Directors of the Corporation has duly adopted this Restated
      Certificate of Incorporation pursuant to the provisions of Section 245 of the
      General Corporation Law of Delaware in the form set forth as
      follows:





“RESTATED
      CERTIFICATE OF INCORPORATION





OF





INSITUFORM
      TECHNOLOGIES, INC.








FIRST:
      The name of the corporation is INSITUFORM TECHNOLOGIES, INC.





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





THIRD:
      The purpose of the corporation is to engage in any lawful act or activity for
      which a corporation may be organized under the General Corporation Law of
      Delaware.





FOURTH:
      The corporation shall be authorized to issue forty- two million (42,000,000)
      shares, consisting of forty million (40,000,000) Class A Common shares, par
      value one cent ($0.01) per share; and two million (2,000,000) Preferred shares,
      par value ten cents ($0.10) per share (“Preferred Stock”).








The
      shares of Preferred Stock shall be issued in one or more series designated
      by
      the Board of Directors without further shareholder action and shall bear such
      terms and designation as the Board of Directors may fix, including dividend
      rates, redemption rights, conversion rights, liquidation preferences, voting
      rights (provided that the Board of Directors may designate that the holders
      of
      one or more series of Preferred Stock shall be entitled as a series to elect
      one
      director and the Board of Directors may at its discretion grant the holders
      of
      one or more series of the corporation’s shares of Preferred Stock the right to
      elect additional directors in the event that dividends on such series shall
      be
      in arrears) and such other terms as the Board of Directors shall determine.
      Any
      shares of Preferred Stock reacquired by the corporation may be reissued without
      further shareholder approval.





FIFTH:
      The name and address of the incorporator are as follows:








Name
            
            AddressRay
                A. Barr
            
            9
                East 40thStreet
              New
                York, New York 10016





SIXTH:
      The following provisions are inserted for the management of the business and
      for
      the conduct of the affairs of the corporation, and for further definition,
      limitation and regulation of the powers of the corporation and of its directors
      and shareholders:





(1)
      The
      number of directors of the corporation shall be such as from time to time shall
      be fixed by, or in the manner provided in, the by-laws; provided, however,
      that
      the number of directors of the corporation shall not be less than six (6) nor
      shall the number of directors of the corporation exceed fifteen (15). Election
      of directors need not be by ballot unless the by-laws so provide.





(2)
      Vacancies in the Board of Directors shall be filled by a majority of the
      directors then in office subject to the procedures set forth in the by-laws
      of
      the corporation. A director shall hold office until the annual meeting for
      the
      year in which his term expires and until his successor shall be elected and
      shall qualify, subject, however, to prior death, resignation, retirement,
      disqualification or removal from office. Any director elected to fill a vacancy
      not resulting from an increase in the number of directors shall have the same
      remaining term as that of his predecessor.





Notwithstanding
      any provision of this Article SIXTH, whenever the holders of any one or more
      series of Preferred Stock issued by the corporation shall have the right, voting
      separately by class or series, to elect directors at an annual or special
      meeting of shareholders or any class or series, the election, term of office,
      filling of vacancies and other features of such directorships shall be governed
      by the terms of this Certificate of Incorporation or the resolution or
      resolutions adopted by the Board of Directors pursuant to Article FOURTH hereof
      applicable thereto.





(3)
      The
      Board of Directors shall have power without the assent or vote of the
      shareholders:





(a)
      To
      make, alter, amend, change, add to or repeal the by-laws of the corporation;
      to
      fix and vary the amount to be reserved for any proper purpose; to authorize
      and
      cause to be executed mortgages and liens upon all or any part of the property
      of
      the corporation; to determine the use and disposition of any





surplus
      or net profits; and to fix the times for the declaration and payment of
      dividends.




(b)
      To
      determine from time to time whether, and to what extent, and at what times
      and
      places, and under what conditions the accounts and books of the corporation
      (other than the stock ledger) or any of them, shall be open to the inspection
      of
      the shareholders.





(4)
      The
      directors at their discretion may submit any contract or act for approval or
      ratification at any annual meeting of shareholders or at any meeting of the
      shareholders called for the purpose of considering any such act or contract,
      and
      any contract or act that shall be approved or be ratified by the vote of the
      holders of a majority of the stock of the corporation which is represented
      in
      person or by proxy at such meeting and entitled to vote thereat (provided that
      a
      lawful quorum of shareholders be there represented in person or by proxy) shall
      be as valid and as binding upon the corporation and upon all the shareholders
      as
      though it had been approved or ratified by every shareholder of the corporation,
      whether or not the contract or act would otherwise be open to legal attack
      because of directors’ interest, or for any other reason.





(5)
      In
      addition to the powers and authorities hereinbefore or by statute expressly
      conferred upon them, the directors are hereby empowered to exercise all such
      powers and do all such acts and things as may be exercised or done by the
      corporation; subject, nevertheless, to the provisions of the statutes of
      Delaware, of this certificate, and to any by-laws from time to time made by
      the
      shareholders; provided, however, that no by-laws so made shall invalidate any
      prior act of the directors which would have been valid if such by-law had not
      been made.





SEVENTH:
      The corporation shall, to the full extent permitted by Section 145 of the
      Delaware General Corporation Law, as amended, from time to time, indemnify
      all
      persons whom it may indemnify pursuant thereto.





EIGHTH:
      Whenever a compromise or arrangement is proposed between this corporation and
      its creditors or any class of them and/or between this corporation and its
      stockholders or any class of them, any court of equitable jurisdiction within
      the State of Delaware, may, on the application in a summary way of this
      corporation or of any creditor or stockholder thereof or on the application
      of
      any receiver or receivers appointed for this corporation under the provisions
      of
      Section 291 of Title 8 of the Delaware Code or on the application of trustees
      in
      dissolution or of any receiver or receivers appointed for this corporation
      under
      the provisions of Section 279 Title 8 of the Delaware Code order a meeting
      of
      the creditors or class of creditors, and/or of the stockholders or class of
      stockholders of this corporation, as the case may be, to be summoned in such
      manner as the said court directs. If a majority in number representing
      three-fourths (3/4) in value of the creditors or class of creditors, and/or
      of
      the stockholders or class of stockholders of this corporation, as the case
      may
      be, agree to any compromise or arrangement and to any reorganization of this
      corporation as consequence of such compromise or arrangement, the said
      compromise or arrangement and the said reorganization shall, if sanctioned
      by
      the court to which the said application has been made, be binding on all the
      creditors or class of creditors, and/or on all the stockholders or class of
      stockholders, of this corporation, as the case may be, and also on this
      corporation.





NINTH:
      The corporation reserves the right to amend, alter, change or repeal any
      provision contained in this certificate of incorporation in the manner now
      or
      hereafter prescribed by law, and all rights and powers conferred herein on
      stockholders, directors and officers are subject to this reserved
      power.








TENTH:
      No
      person who is or was at any time a director of the corporation shall be
      personally liable to the corporation or its stockholders for monetary damages
      for any breach of fiduciary duty by such person as a director; provided,
      however, that, unless and except to the extent otherwise permitted from time
      to
      time by applicable law, the provisions of this Paragraph Tenth shall not
      eliminate or limit the liability of a director (i) for breach of the director’s
      duty of loyalty to the corporation or its stockholders, (ii) for any act or
      omission by the director which is not in good faith or which involves
      intentional misconduct or a knowing violation of law, (iii) under Section 174
      of
      the General Corporation Law of the State of Delaware, (iv) for any transaction
      from which the director derived an improper personal benefit or (v) for any
      act
      or omission occurring prior to the date this Paragraph Tenth becomes effective.
      No amendment to or repeal of this Paragraph Tenth shall apply to or have any
      effect on the liability or alleged liability of any director of the corporation
      for or with respect to any act or omission of such director occurring prior
      to
      such amendment or repeal.





ELEVENTH:
      Subject to the rights of the holders of any class or series of Preferred Stock
      expressly set forth in this Certificate of Incorporation, the Certificate of
      Designation related to such class or series of Preferred Stock or as otherwise
      required by law, any action required or permitted to be taken by the
      shareholders of the corporation must be effected exclusively at a duly called
      annual or special meeting of such shareholders and may not be effected by any
      consent in writing by such shareholders. This Article ELEVENTH may not be
      repealed or amended in any respect, and no provision inconsistent with this
      Article ELEVENTH may be adopted, unless such action is approved by the
      affirmative vote of the holders of not less than eighty (80) percent of the
      combined voting power of the then outstanding shares of capital stock of the
      corporation entitled to vote generally in the election of
      directors.”





IN
      WITNESS WHEREOF, the Corporation has caused this Restated Certificate of
      Incorporation to be executed on its behalf by Anthony W. Hooper, its President,
      and attested by Howard Kailes, its Secretary, as of this 8th day of June,
      1999.





ATTEST:








/s/
                Howard Kailes
            
            /s/
                Anthony W. HooperHoward
                Kailes
            
            Anthony
                W. HooperSecretary
            
            President








**CERTIFICATE
      OF AMENDMENT**





**OF**





**RESTATED
      CERTIFICATE OF INCORPORATION**





**OF**





**INSITUFORM
      TECHNOLOGIES, INC.**








INSITUFORM
      TECHNOLOGIES, INC., a corporation organized and existing by virtue of the
      General Corporation Law of the State of Delaware (the “Corporation”), pursuant
      to the provisions of the General Corporation Law of the State of Delaware (the
      “GCL”) DOES HEREBY CERTIFY as follows:





FIRST:
      The Restated Certificate of Incorporation of the Corporation is hereby amended
      by deleting the first paragraph of Article FOURTH in its entirety and
      substituting therefor a new first paragraph of Article FOURTH in the following
      form:





“FOURTH:
      The corporation shall be authorized to issue sixty-two million (62,000,000)
      shares consisting of sixty million (60,000,000) Class A common shares, par
      value
      one cent ($0.01) per share; and two million (2,000,000) Preferred shares, par
      value ten cents ($0.10) per share (“Preferred Stock”).”





SECOND:
      The amendments to the Restated Certificate of Incorporation of the Corporation
      set forth in this Certificate of Amendment have been duly adopted in accordance
      with the applicable provisions of Section 242 of the GCL: (a) the Board of
      Directors of the Corporation having duly adopted resolutions setting forth
      the
      proposed amendments and declaring their advisability by unanimous written
      consent of the Board of Directors of the Corporation dated March 31, 2000 in
      conformity with the By-laws of the Corporation and (b) the stockholders of
      the
      Corporation having duly adopted such amendments by the affirmative vote of
      the
      holders of a majority of the outstanding stock entitled to vote thereon, on
      May
      25, 2000, taken at the Corporation’s annual meeting of stockholders duly called
      and held upon notice in accordance with Section 222 of the GCL.





IN
      WITNESS WHEREOF, the Corporation has caused this Certificate to be executed
      on
      its behalf by Anthony W. Hooper, its President, and attested by Howard Kailes,
      its Secretary, as of this 25th day of May, 2000.





ATTEST:








/s/
                Howard Kailes
            
            /s/
                Anthony W. HooperHoward
                Kailes
            
            Anthony
                W. HooperSecretary
            
            President





**CERTIFICATE
      OF AMENDMENT**





**OF**





**RESTATED
      CERTIFICATE OF INCORPORATION**





**OF**





**INSITUFORM
      TECHNOLOGIES, INC.**








INSITUFORM
      TECHNOLOGIES, INC. ,
      a
      corporation organized and existing by virtue of the General Corporation Law
      of
      the State of Delaware (the “Corporation”), pursuant to the provisions of the
      General Corporation Law of the State of Delaware (the “General Corporation Law”)
      does hereby certify as follows:





**FIRST:**  The
      Restated Certificate of Incorporation of the Corporation is hereby amended
      by
      deleting Article SEVENTH in its entirety and substituting therefor a new Article
      SEVENTH in the following form:





“SEVENTH:
      The corporation shall, to the full extent permitted by Section 145 of the
      Delaware General Corporation Law, as amended, from time to time, indemnify
      the
      corporation’s officers and directors. The corporation may, to the full extent
      permitted by Section 145 of the Delaware General Corporation Law, as amended,
      from time to time, indemnify all other persons whom it may indemnify pursuant
      thereto.”





**SECOND:** The
      amendment to the Restated Certificate of Incorporation of the Corporation set
      forth in this Certificate of Amendment has been duly adopted in accordance
      with
      the applicable provisions of Section 242 of the General Corporation Law: (a)
      the
      Board of Directors of the Corporation, at a meeting on January 26, 2005, having
      duly adopted resolutions setting forth the proposed amendment and declaring
      its
      advisability; and (b) the stockholders of the Corporation having duly adopted
      such amendment by the affirmative vote of the holders of a majority of the
      outstanding stock entitled to vote thereon, taken at the Corporation’s annual
      meeting of stockholders duly called and held on April 27, 2005, upon notice
      in
      accordance with Section 222 of the General Corporation Law.





**IN
      WITNESS WHEREOF** ,
      the
      Corporation has caused this Certificate to be executed on its behalf by David
      F.
      Morris, its Vice President, General Counsel and Secretary, as of this
      27 th day of
      April, 2005.








INSITUFORM
                TECHNOLOGIES, INC./s/
                David F. MorrisDavid
                F. MorrisVice
                President, General Counsel and Secretary