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                              UNITED STATES
                    SECURITIES AND EXCHANGE COMMISSION
                          Washington, DC 20549


                                 FORM 8-K


                         CURRENT REPORT PURSUANT
                       TO SECTION 13 OR 15(D) OF THE
                      SECURITIES EXCHANGE ACT OF 1934

              Date of Report (Date of earliest event reported):
                              August 8, 2005
                              --------------

                       WESTAMERICA BANCORPORATION
                       --------------------------
          (Exact Name of Registrant as Specified in Its Charter)

                                CALIFORNIA
                                ----------
              (State or Other Jurisdiction of Incorporation)


                001-9383                       94-2156203
                --------                       ----------
        (Commission File Number)    (IRS Employer Identification No.)


         1108 Fifth Avenue, San Rafael, California          94901
         ----------------------------------------------------------
          (Address of Principal Executive Offices)        (Zip Code)


                               (707) 863-6000
                               --------------
            (Registrant's Telephone Number, Including Area Code)


   Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any
of the following provisions:

      []  Written communications pursuant to Rule 425 under the Securities
          Act (17 CFR 230.425)

      []  Soliciting material pursuant to Rule 14a-12 under the Exchange
          Act (17 CFR 240.14a-12)

      []  Pre-commencement communications pursuant to Rule 14d-2(b) under
          the Exchange Act (17 CFR 240.14d-2(b))

      []  Pre-commencement communications pursuant to Rule 13e-4(c) under
          the Exchange Act (17 CFR 240.13e-4c))


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Exhibits
- ---------

99.1 Press release dated August 8, 2005


Item 5.02:  Departure of Principal Officer
- ------------------------------------------

On August 8, 2005 Westamerica Bancorporation reported that Hans Tjian, Senior
Vice President, Operations and Systems Division Manager, passed away from a
sudden illness.  A copy of the press release is attached as Exhibit 99.1 to
this Form 8-K and is incorporated herein by reference.





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                                 Signatures

Pursuant to the Securities Exchange Act of 1934, the registrant has
duly caused this report to be signed on its behalf by the undersigned
hereunto duly authorized.

Westamerica Bancorporation

/s/    DENNIS R. HANSEN
- ------------------------------------
Dennis R. Hansen
Senior Vice President and Controller
August 8, 2005




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INDEX TO EXHIBITS
- -----------------

                                                         Sequentially
Exhibit No.             Description                      Number Page
- -----------             -------------------------        -------------
  (99.1)                 Press release dated                   5
                         August 8, 2005



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Exhibit 99.1:
- -------------

FOR IMMEDIATE RELEASE
August 8, 2005


WESTAMERICA NOTIFICATION OF SENIOR MANAGEMENT CHANGE


San Rafael, CA:	Westamerica Bancorporation (NASDAQ: WABC) reported today Hans
Tjian, its Senior Vice President, Operations and Systems Division Manager,
passed away on August 5, 2005 from a sudden illness. Mr. Tjian had served
Westamerica in such capacity since 1989.

"Hans served Westamerica with great conviction, foresight, and leadership. His
contributions played a critical role in leading Westamerica to our current top-
tier performance levels. We will miss Hans deeply, on both a professional and
personal level," said Chairman, President & CEO David Payne.

Westamerica Bancorporation Web Address: www.westamerica.com

For additional information contact:
Westamerica Bancorporation
Robert A. Thorson  -  SVP & Treasurer
	707-863-6840



FORWARD-LOOKING INFORMATION:

The following appears in accordance with the Private Securities Litigation
Reform Act of 1995:
   This press release may contain forward-looking statements about the Company,
including descriptions of plans or objectives of its management for future
operations, products or services, and forecasts of its revenues, earnings or
other measures of economic performance.  Forward-looking statements can be
identified by the fact that they do not relate strictly to historical or current
facts.  They often include the words "believe," "expect," "anticipate,"
"intend," "plan," "estimate," or words of similar meaning, or future or
conditional verbs such as "will," "would," "should," "could," or "may."
   Forward-looking statements, by their nature, are subject to risks and
uncertainties. A number of factors - many of which are beyond the Company's
control - could cause actual conditions, events or results to differ
significantly from those described in the forward-looking statements.  The
Company's most recent annual and quarterly reports filed with the Securities and
Exchange Commission, including the Company's Form 10-Q for the quarter ended
March 31, 2005 and Form 10-K for the year ended December 31, 2004, describe some
of these factors, including certain credit, market, operational, liquidity and
interest rate risks associated with the Company's business and operations.
Other factors described in these reports include changes in business and
economic conditions, competition, fiscal and monetary policies,
disintermediation, legislation including the Sarbanes-Oxley Act of 2002 and the
Gramm-Leach-Bliley Act of 1999, the combination of the former Redwood Empire
Bancorp and other mergers and acquisitions.
   Forward-looking statements speak only as of the date they are made.  The
Company does not undertake to update forward-looking statements to reflect
circumstances or events that occur after the date forward looking statements are
made.

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