1 EXHIBIT 4.5 AMENDMENT 1 TO THE ADOPTION AGREEMENT FOR CUSTOM BENEFIT SERVICES OF HOUSTON, INC. STANDARDIZED 401(k) PROFIT SHARING PLAN AND TRUST This amendment is made this first day of September, 1999 by Prosperity Bancshares, Inc., a Texas...

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                                                                     EXHIBIT 4.5





                               AMENDMENT 1 TO THE
                             ADOPTION AGREEMENT FOR
                    CUSTOM BENEFIT SERVICES OF HOUSTON, INC.
                STANDARDIZED 401(k) PROFIT SHARING PLAN AND TRUST


This amendment is made this first day of September, 1999 by Prosperity
Bancshares, Inc., a Texas corporation.

         WHEREAS, the Employer maintains the Prosperity Bancshares, Inc. 401(k)
Profit Sharing Plan (hereinafter referred to as the "Plan"); and

         WHEREAS, under the terms and provisions of the Plan, the Employer has
the right to amend the Plan; and

         WHEREAS, after review and consideration, it has been determined that an
amendment to the Plan is in the best interest of the Plan's Participants;

         NOW, THEREFORE, BE IT RESOLVED, that the Plan is amended as follows
effective September 1, 1999:

         The existing Section B6 of the Adoption Agreement for the Custom
Benefit Group of Houston, Inc. Regional Prototype Standardized 401(k) Profit
Sharing Plan and Trust shall be amended as follows:

         B6       NAME(S) OF TRUSTEE(S)

                  a.       Xxxxxxx Xxxxxx
                           --------------
                  b.
                           --------------
                  c.
                           --------------
                  d.
                           --------------
                  e.
                           --------------


IN WITNESS WHEREOF, this Amendment has been executed the day and year first
written above.

PROSPERITY BANCSHARES, INC.

 /s/ Xxxxx Xxxxxx
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Xxxxx Xxxxxx

Vice President
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