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                                                                    EXHIBIT 99.1


                               NORTH BAY BANCORP
     THIS REVOCABLE PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS


     The undersigned hereby appoints Eugene B. Ceccotti and Dean J. Moser, and
each of them, with full power of substitution, as proxies of the undersigned,
to attend the Special Meeting of Shareholders of North Bay Bancorp ("North
Bay") to be held at 350 Ignacio Boulevard, Novato, California 94949, on
Thursday, March 23, 1995 at 5:00 p.m., and any adjournment or postponement
thereof, and to vote the number of shares the undersigned would be entitled to
vote if personally present upon the following items and to vote according to
their discretion on any other matter which may properly be presented for
action at said meeting or any adjournment or postponement thereof:

     1. TO ADOPT AND APPROVE THE AGREEMENT AND PLAN OF REORGANIZATION DATED AS
        OF DECEMBER 8, 1994, BY AND AMONG WESTAMERICA BANCORPORATION
        ("WESTAMERICA"), NORTH BAY AND NOVATO NATIONAL BANK, AN AGREEMENT OF
        MERGER BETWEEN WESTAMERICA AND NORTH BAY, AND THE TRANSACTIONS
        CONTEMPLATED THEREBY, INCLUDING, WITHOUT LIMITATION, CERTAIN PROVISIONS
        BENEFITTING DIRECTORS, EXECUTIVE OFFICERS AND EMPLOYEES OF NORTH BAY,
        THE PROPOSED MERGER OF NORTH BAY WITH AND INTO WESTAMERICA AND THE
        AMENDMENT OF THE NORTH BAY BANCORP 1985 STOCK OPTION PLAN.
        
       / /    FOR               / /     AGAINST             / /     ABSTAIN

                (To be completed and signed on the reverse side)

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                                                                    EXHIBIT 99.1
                                                                    
                          (Continued from other side)

     THIS PROXY WILL BE VOTED AS SPECIFIED, OR IF NO CHOICE IS SPECIFIED, THIS
PROXY WILL BE VOTED "FOR" THE PROPOSAL SET FORTH.  Please sign exactly as name
appears.  When shares are held by joint tenants, both should sign.  When
signing as attorney, executor, administrator, 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 
partnership name by authorized person.

                          Dated: 
                                 ----------------------------------------, 1995
                          Signature
                                   --------------------------------------------
                          Signature, if held jointly
                                   --------------------------------------------

     SHAREHOLDERS ARE URGED TO MARK, DATE, SIGN AND RETURN THIS PROXY IN THE
ENVELOPE PROVIDED, WHICH REQUIRES NO POSTAGE IF MAILED IN THE UNITED STATES.