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 ending March 31, 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.




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