EXHIBIT 99.1


                    CERTIFICATION OF CHIEF EXECUTIVE OFFICER

         Pursuant to 18 U.S.C. ss. 1350, as created by Section 906 of the
Sarbanes-Oxley Act of 2002, the undersigned officer of IDEX Corporation (the
"Company") hereby certifies, to such officer's knowledge, that:

         (i) the accompanying Quarterly Report on Form 10-Q of the Company for
       the quarterly period ended March 31, 2003 (the "Report") fully complies
       with the requirements of Section 13(a) or Section 15(d), as applicable,
       of the Securities Exchange Act of 1934, as amended; and

         (ii) the information contained in the Report fairly presents, in all
       material respects, the financial condition and results of operations of
       the Company.


May 13, 2003                                /s/ Dennis K. Williams
                                            ------------------------------------
                                            Dennis K. Williams
                                            Chairman, President and
                                            Chief Executive Officer