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                                                                    EXHIBIT 99.1
                                 PINEMONT BANK
                        SPECIAL MEETING OF SHAREHOLDERS
                                       , 1997
              Proxy Solicited on Behalf of the Board of Directors
  The undersigned hereby (a) acknowledges receipt of the Notice of Special
Meeting of Shareholders of Pinemont Bank (the "Bank") to be held on          ,
1997 and the Proxy Statement/Prospectus in connection therewith, each dated
         , 1997, (b) appoints Stanley D. Stearns, Jr., Robert A. Skilton and
Robert J. Adam, or any of them, as Proxies, each with the power to appoint a
substitute, (c) authorizes the Proxies to represent and vote, as designated
below, all the shares of Bank Common Stock (as defined in the Proxy
Statement/Prospectus), held of record by the undersigned on          , 1997 at
the Special Meeting and at any adjournment(s) thereof, and (d) revokes any
proxies heretofore given.

1. Approval and adoption of the Agreement and Plan of Merger dated as of April
   28, 1997, by and among the Bank, Southwest Bancorporation of Texas, Inc.
   (the "Company") and Southwest Bank of Texas National Association, a wholly-
   owned subsidiary of the Company ("SW Bank"), pursuant to which the Bank will
   merge with and into SW Bank which shall be the surviving entity, and
   whereupon the shareholders of the Bank will receive 0.625 of a share of
   Company Common Stock (as defined in the Proxy Statement/Prospectus) in
   exchange for each share of Bank Common Stock:
                      [_] FOR   [_] AGAINST   [_] ABSTAIN
 
2. In their discretion, the Proxies are authorized to vote upon such other
   business as may properly come before the meeting or any adjournment(s) or
   postponement(s) thereof.
 
                  (Continued and to be signed on reverse side)
                           (Continued from other side)
 
  THIS PROXY WILL BE VOTED AS SPECIFIED. IF NO SPECIFICATION IS INDICATED, THIS
PROXY WILL BE VOTED FOR THE APPROVAL AND ADOPTION OF THE AGREEMENT AND PLAN OF
MERGER AND, IN THE DISCRETION OF THE PROXIES, ON ANY OTHER BUSINESS.
 
                                   DATED                                 , 1997
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                                   Signature

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                                   Signature if held jointly
 
                                   IMPORTANT. Please date this proxy and sign
                                   exactly as your name or names appear on
                                   your stock certificate(s). If stock is held
                                   jointly, all holders must execute this
                                   proxy. Executors, administrators, trustees,
                                   guardians and others signing in a
                                   representative capacity, please so indicate
                                   when signing.
 
 PLEASE SIGN, DATE AND RETURN THIS PROXY PROMPTLY IN THE ACCOMPANYING POSTPAID
                                    ENVELOPE