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 on Form 10-K of Kronos  Incorporated
(the  "Company") for the fiscal year ended  September 30, 2003 as filed with the
Securities  and  Exchange  Commission  on the date  hereof (the  "Report"),  the
undersigned,  Mark S. Ain, Chief Executive  Officer of the Company,  and Paul A.
Lacy,  Executive Vice President,  Chief Financial and Administrative  Officer of
the Company, each hereby certifies, pursuant to 18 U.S.C. Section 1350, that:

(1)  The Report fully complies with the  requirements  of Section 13(a) or 15(d)
     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.



                                           /s/ Mark S. Ain
                                           ------------------------------------
Dated: December 23, 2003                       Mark S. Ain
                                           Chief Executive Officer


                                           /s/ Paul A. Lacy
                                           ------------------------------------
Dated: December 23, 2003                       Paul A. Lacy
                                           Executive Vice President, Chief
                                           Financial and Administrative Officer


A signed  original of this  written  statement  required by Section 906 has been
provided to Kronos  Incorporated and will be retained by Kronos Incorporated and
furnished to the Securities and Exchange Commission or its staff upon request.