FIRST AMENDMENT TO CREDIT AGREEMENT

THIS FIRST AMENDMENT TO CREDIT AGREEMENT dated as of October 15, 2009 (the “ Amendment ”) is entered into among Insituform Technologies, Inc., a Delaware corporation (the “ Borrower ”), the Guarantors, the Lenders party hereto and Bank of America, N.A., as Administrative Agent.  All capitalized terms used herein and not otherwise defined herein shall have the meanings given to such terms in the Credit Agreement (as defined below).

WHEREAS, the Borrower, the Guarantors, the Lenders and Bank of America, N.A., as Administrative Agent entered into that certain Credit Agreement dated as of March 31, 2009 (as amended and modified from time to time, the “ Credit Agreement ”);

WHEREAS, the Borrower has requested that the Lenders amend the Credit Agreement as set forth below;

NOW, THEREFORE, in consideration of the premises and the mutual covenants contained herein, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree as follows:

1.            Amendments .  The Credit Agreement is hereby amended as follows:

(a)            Section 1.01 .  The following definitions of “ Canadian Acquisition ”, and “ Canadian Subsidiary ” are hereby added to Section 1.01 of the Credit Agreement in the appropriate alphabetical order:

“ Canadian Acquisition ” means the Acquisition by the Canadian Subsidiary of the operating assets of the Camrose, Alberta operation of Garneau Inc. for a purchase price not to exceed 12,350,000 Canadian Dollars.

“ Canadian Subsidiary ” means Bayou Perma-Pipe Canada, Ltd.

(b)            Section 8.02 .  The “.” at the end of clause (i) in Section 8.02 of the Credit Agreement is hereby replaced with “; and” and the following new clause (j) is hereby added immediately following clause (i) to read as follows:

(j)           the Canadian Acquisition.

(e)     Priority Debt in an aggregate principal amount not to exceed the lesser of (i) $20,000,000 at any time outstanding and (ii) the amount of Priority Debt permitted by the Note Purchase Agreement;

2.             Conditions Precedent .  This Amendment shall be effective upon satisfaction of the following conditions precedent:

     (a)           The Administrative Agent shall have received counterparts of this Amendment executed by the Borrower, the Guarantors, the Required Lenders and the Administrative Agent.

     (b)           The Administrative Agent shall have received a certified copy of the executed asset purchase agreement for the Canadian Acquisition in form and substance reasonably acceptable to the Administrative Agent.

     (c)           The Administrative Agent shall have received (i) for the account of each Lender executing this Amendment on or before 12 noon (CST), October 15, 2009, a fee of 0.10% on the amount of such Lender’s outstanding Term Loan and Commitment and (ii) any other reasonable fees and expenses owing to the Administrative Agent, the Lenders or BAS.

3.             Miscellaneous .

     (b)           Each Guarantor (a) acknowledges and consents to all of the terms and conditions of this Amendment, (b) affirms all of its obliga