EXHIBIT 31.1
                                CERTIFICATION OF
                             CHIEF EXECUTIVE OFFICER

I, Leon Zimmerman, certify that:

1. I have reviewed this quarterly report on Form 10-Q of First Financial Bancorp
for the quarter ended June 30, 2004;

2. Based on my  knowledge,  this  quarterly  report  does not contain any untrue
statement of a material fact or omit to state a material fact  necessary to make
the statements made, in light of the  circumstances  under which such statements
were made, not  misleading  with respect to the period covered by this quarterly
report;

3.  Based  on my  knowledge,  the  financial  statements,  and  other  financial
information  included in this quarterly  report,  fairly present in all material
respects the financial  condition,  results of operations  and cash flows of the
registrant as of, and for, the periods presented in this quarterly report;

4.  The  registrant's  other  certifying  officer  and  I  are  responsible  for
establishing and maintaining  disclosure  controls and procedures (as defined in
Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrant and we have:

         (a) designed such disclosure  controls and  procedures,  or caused such
disclosure  controls and  procedures to be designed  under our  supervision,  to
ensure that  material  information  relating to the  registrant,  including  its
consolidated subsidiaries,  is made known to us by others within those entities,
particularly during the period in which this quarterly report is being prepared;

         (b) evaluated the effectiveness of the registrant's disclosure controls
and  procedures  and  presented  in  this  report  our  conclusions   about  the
effectiveness  of the disclosure  controls and procedures,  as of the end of the
period covered by this report based on such evaluation; and

         (c) disclosed in this quarterly  report any change in the  registrant's
internal control over financial  reporting that occurred during the registrant's
most recent fiscal quarter that has materially affected, or is reasonably likely
to materially affect the registrant's internal control over financial reporting;
and

5. The registrant's other certifying officer and I have disclosed,  based on our
most recent  evaluation of internal  control over  financial  reporting,  to the
registrant's  auditors  and the audit  committee  of the  registrant's  board of
directors (or persons performing the equivalent functions):

         (a) all significant  deficiencies and material weaknesses in the design
or operation of internal  control over financial  reporting which are reasonably
likely  to  adversely  affect  the  registrant's  ability  to  record,  process,
summarize and report financial information; and

         (b) any fraud,  whether or not material,  that  involves  management or
other employees who have a significant role in the registrant's internal control
over financial reporting.

                                           /s/Leon Zimmerman
                                           Leon Zimmerman
                                           President and Chief Executive Officer
                                           (Principal Executive Officer)


Dated:  August 12, 2004



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