EXHIBIT 32.1

                             FIRST FINANCIAL BANCORP
              CERTIFICATION OF CHIEF EXECUTIVE OFFICER 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 First Financial Bancorp (the
"Company")  on Form 10-Q for the period ended  September 30, 2004, as filed with
the Securities  and Exchange  Commission on the date hereof (the  "Report"),  I,
Leon S.  Zimmerman,  Chief  Executive  Officer of the Company,  hereby  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) 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.




November 12, 2004                       /s/  Leon S. Zimmerman
                                        ---------------------------
                                          Chief Executive Officer


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