EXHIBIT 99.1

                         ______________________________

                                     PROXY
                          PROSPERITY BANCSHARES, INC.
                                 HOUSTON, TEXAS

                        Special Meeting of Shareholders
                               ____________, 2001

           This Proxy is Solicited by the Board of Directors for use
       at the Special Meeting of Shareholders on _________________, 2001
                         ______________________________

     The undersigned shareholder of Prosperity Bancshares, Inc. ("Prosperity")
hereby constitutes and appoints Tracy T. Rudolph and David Zalman, and each of
them, attorneys, agents and proxies with full power of substitution, to vote the
number of shares of common stock of Prosperity which the undersigned would be
entitled to vote if personally present at the Special Meeting of Shareholders of
Prosperity to be held at _____ _.m., local time, on ____________, _____________,
2001, and at any adjournments thereof (the "Meeting"), with respect to the
proposals described in the Joint Proxy Statement-Prospectus and the Notice of
Special Meeting of Shareholders both dated ____________, 2001, timely receipt of
which is acknowledged, in the manner specified below.

     1.   Approval of the Agreement and Plan of Reorganization dated as of
November 8, 2000 by and between Prosperity Bancshares, Inc. and Commercial
Bancshares, Inc. (the "Agreement") and the issuance of shares of Prosperity
common stock to shareholders of Commercial Bancshares, Inc. upon the terms and
subject to the conditions set forth in the Agreement as more specifically
described in the Joint Proxy Statement-Prospectus.

                  [_] For     [_]  Against      [_]  Abstain

     2.   In their sole discretion on such other matters as may properly come
before the Meeting or any adjournments thereof.

                  [_] Authorized                [_]  Withhold Authority

     This Proxy, when properly executed, will be voted in the manner directed
herein by the undersigned shareholder.  If no direction is made, this Proxy will
be voted "FOR" Proposal 1 and with discretionary authority on all other matters
that may properly come before the Meeting or any adjournments thereof.

     Please date and sign exactly as your name appears on the certificates
representing your shares of common stock of Prosperity.  If shares are held
jointly, each shareholder must sign.  When signing as attorney, trustee or
guardian, please give full title as such.  If a corporation, please sign in full
corporate name by president or other authorized officer.  If a partnership,
please sign in full partnership name by authorized person.


                              _______________________________
                              (Signature of Shareholder)


                              _______________________________
                              (Signature of Shareholder)

                              Dated ________________, 2001


THIS PROXY IS SOLICITED ON BEHALF OF THE PROSPERITY'S BOARD OF DIRECTORS AND MAY
BE REVOKED BY THE SHAREHOLDER PRIOR TO ITS EXERCISE.