EXHIBIT 32.1


                    CERTIFICATION OF CHIEF EXECUTIVE OFFICER
                       PURSUANT TO 18 U.S.C. SECTION 1350

         In connection with the quarterly report of Input/Output, Inc. (the
"Company") on Form 10-Q for the period ended June 30, 2004, as filed with the
Securities and Exchange Commission on the date hereof (the "Report"), I, Robert
P. Peebler, President and Chief Executive Officer of the Company, 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 Report fully complies with the requirements of Section 13(a) or
         15(d), as applicable, of the Securities Exchange Act of 1934; and

2.       The information contained in the Report fairly presents, in all
         material respects, the financial condition and results of operations of
         the Company.


         Date: August 9, 2004                     /s/ Robert P. Peebler
                                       -----------------------------------------
                                       Robert P. Peebler
                                       President and Chief Executive Officer