Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the quarterly report on Form 10-Q of Insituform Technologies, Inc. (the “Company”) for the quarter ended September 30, 2005 as filed with the Securities and Exchange Commission on the date hereof (the “Form 10-Q”), I, Thomas S. Rooney, Jr., President and Chief Executive Officer of the Company, hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

(1)	the Form 10-Q fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and
(2)	information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Company.

Dated: October 31, 2005

/s/ Thomas S. Rooney, Jr.

Thomas S. Rooney, Jr.

President and Chief Executive Officer