Exhibit 99.1


     CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002



In connection with the filing of the Quarterly Report on Form 10-Q for the
quarter ended June 30, 2002 (the "Report") by Kirby Corporation (the "Company"),
each of the undersigned hereby certifies that:

      1.    The Report fully complies with the requirements of Section 13(a) or
            15(d) of the Securities Exchange Act of 1934, as amended; and

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


                                           /s/ J. H. PYNE
                                           -------------------------------------
                                           J. H. Pyne
                                           President and Chief Executive Officer




                                           /s/ NORMAN W. NOLEN
                                           -------------------------------------
                                           Norman W. Nolen
                                           Executive Vice President, Treasurer
                                               and Chief Financial Officer

Dated: August 9, 2002