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 annual report of Insituform Technologies, Inc. (the
"COMPANY") on Form 10-K for the year ended December 31, 2003 as filed with the
Securities and Exchange Commission on the date hereof (the "FORM 10-K"), I,
Thomas S. Rooney, Jr., President and Chief Executive Officer of the Company,
hereby certify, as of the date hereof, that:

                  (1)      the Form 10-K 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-K fairly
                           presents, in all material respects, the financial
                           condition and results of operations of the Company.

Dated: March 15, 2004

                                           /s/ Thomas S. Rooney, Jr.
                                           -------------------------------------
                                           Thomas S. Rooney, Jr.
                                           President and Chief Executive Officer