Exhibit 4.2


                          AMENDMENT TO RIGHTS AGREEMENT

         This Amendment, dated as of September 7, 2004 (the "Amendment"), is to
the Rights Agreement dated as of June 15, 2001 (the "Rights Agreement"), between
First Financial Bancorp, a California corporation ( "the Company"), and Mellon
Investor Services, LLC (the "Rights Agent").

         WHEREAS, the Board of Directors of the Company has approved an
Agreement and Plan of Merger dated as of September 7, 2004 among Placer Sierra
Bancorp ("PSB"), a California corporation, its subsidiary Placer Sierra Bank
("PS Bank"), the Company, and the Company's subsidiary Bank of Lodi, N.A.
("BOL") providing for the merger of the Company with and into PSB and the merger
of BOL with and into PS Bank pursuant to a related merger agreement (such
agreements together, the "Merger Agreements");

         WHEREAS, the Merger Agreements contemplate that the Company, at the
time such agreements are executed, shall have taken all actions necessary to
prevent the Merger Agreements and the transactions contemplated therein from
triggering the Rights (as defined in the Rights Agreement) outstanding under the
Rights Agreement;

         WHEREAS, the Board of Directors has determined that this Amendment is
in the best interests of the Company and its shareholders; and

         WHEREAS, the Company and the Rights Agent have determined that,
pursuant to Section 27 of the Rights Agreement, the Rights Agreement may be
amended as set forth herein without the approval of the holders of the Rights.

         NOW, THEREFORE, in consideration of the premises and the mutual
agreements set forth herein, the Company and the Rights Agent hereby agree as
follows:

         1. This Amendment shall become effective on the date that the Company
and PSB have both executed the Merger Agreements, immediately before such
execution.

         2. Subsection 1(a) of the Rights Agreement is hereby amended to include
the following additional sentence to immediately follow the current language
therein: "Notwithstanding the foregoing, neither Placer Sierra Bancorp, a
California corporation, nor any of its Affiliates or Associates, shall be an
`Acquiring Person.'"

         3. Section 1 of the Rights Agreement is hereby amended to include a new
Subsection 1(aa) which shall read as follows: "`Section 11(a)(ii) Event' shall
mean any Trigger Event or any other event set forth in Section 11(a)(ii)."

         4. Section 1 of the Rights Agreement is hereby amended to include a new
Subsection 1(bb) which shall read as follows:

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         "Section 13 Event" shall mean any event described in clause (i), (ii),
         (iii) or (iv) of Section 13(a) of this Agreement, other than the
         delivery, execution or performance or consummation of any of the
         transactions contemplated in the Agreement and Plan of Reorganization
         dated as of September 7, 2004 between Placer Sierra Bancorp, a
         California corporation and the Company and the related Merger
         Agreement.

         5. Section 1 of the Rights Agreement is hereby amended to include a new
Subsection 1(cc) which shall read as follows: "`Triggering Event'" shall mean
any Section 11(a)(ii) Event or any Section 13 Event."

         6. The Rights Agreement is hereby amended to include a new Subsection
(v) to Section 11(a) thereof which shall read as follows:

         (v) Notwithstanding anything in this Agreement to the contrary, the
         execution, delivery, performance or consummation of any of the
         transactions contemplated in the Agreement and Plan of Reorganization
         dated as of September 7, 2004 between Placer Sierra Bancorp and the
         Company and the related Merger Agreement will not be deemed to be a
         TriggeringEvent.

         7. Section 13 of the Rights Agreement is hereby amended to include a
new Subsection 13(f) which shall read as follows:

         (f) Notwithstanding anything in this Agreement to the contrary, this
         Section 13 shall not be applicable to the execution, delivery, or the
         performance or consummation of any of the transactions contemplated in,
         the Agreement and Plan of Reorganization dated as of September 7, 2004
         between Placer Sierra Bancorp and the Company and the related Merger
         Agreement none of such events or occurrences shall be deemed to be a
         Triggering Event.

         8. The form of Summary of Rights to Purchase Preferred Shares attached
as Exhibit C to the Rights Agreement is hereby replaced in its entirety by the
form of Summary of Rights to Purchase Common Shares attached as Exhibit A
hereto.

         9. As promptly as practicable following the date of this Amendment, the
Company shall take all appropriate actions to cause the legend on the
certificates for the Common Stock referring to the Rights Agreement to make
reference to this Amendment.

         10. This Amendment shall be limited solely to the matters expressly set
forth herein and shall not (a) prejudice any right or rights which the Company
may now have or may in the future have under or in connection with the Rights
Agreement or any instruments or agreements referred to therein or (b) except to
the extent expressed as set forth herein, modify the Rights Agreement or any
Rights, or any instruments or agreements referred to therein.

         11. Unless defined herein, all capitalized terms shall have the
meanings provided in the Rights Agreement.

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<PAGE>


         12. This Amendment shall be deemed to be a contract under the laws of
the State of New York and for all purposes shall be governed by and construed in
accordance with the laws of such State applicable to contracts to be made and
performed entirely within such State.

         13. This Amendment may be executed in any number of counterparts and
each of such counterparts shall for all purposes be deemed to be an original,
and all such counterparts shall together constitute but one and the same
instrument. Signatures by facsimile transmission are deemed acceptable.

         14. This Amendment shall be for the sole and exclusive benefit of the
Company, the Rights Agent and the registered holders of the Rights Certificates
(and, prior to the Distribution Date, the Company's common shares). Nothing in
this Amendment shall be construed to give any person other than the Company, the
Rights Agent and the registered holders of the Rights Certificates (and, prior
to the Distribution Date, the Company's common shares) any legal or equitable
right, remedy or claim under this Amendment and the Merger Agreement.

         IN WITNESS WHEREOF, the parties have caused this Amendment to be duly
executed and their respective corporate seals to be hereto affixed and attested,
all as of the date and year first above written.

                             FIRST FINANCIAL BANCORP


                             By:      /s/LEON J. ZIMMERMAN
                                  _______________________________________
                                         Leon J. Zimmerman

                             Its:     PRESIDENT & CHIEF EXECUTIVE OFFICER
                                  _______________________________________

                             MELLON INVESTOR SERVICES, LLC


                             By:         /s/CECIL D. BOBEY
                                  _______________________________________
                                            Cecil D. Bobey

                             Its:     ASSISTANT VICE PRESIDENT
                                  _______________________________________


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