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 Annual Report of First Financial Bancorp (the
"Company") on Form 10-K for the period ended December 31, 2003, as filed with
the Securities and Exchange Commission on the date hereof (the "Report"), I,
Leon Zimmerman, President and 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.

/s/  Leon Zimmerman
Leon Zimmerman
Chief Executive Officer
March 25, 2004


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