EXHIBIT 99.1

                            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 of Insituform Technologies, Inc. (the
"COMPANY") on Form 10-Q for the period ending March 31, 2003 as filed with the
Securities and Exchange Commission on the date hereof (the "FORM 10-Q"), I,
Anthony W. Hooper, Chairman and Chief Executive Officer of the Company, hereby
certify, as of the date hereof, 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:  May 15, 2003
                                          /s/ Anthony W. Hooper
                                          -------------------------------------
                                          Anthony W. Hooper
                                          Chairman and Chief Executive Officer