<DOCUMENT>
<TYPE>EX-11
<SEQUENCE>2
<FILENAME>exh11.txt
<DESCRIPTION>WESTAMERICA EXH. 11 FOR 6-30-2004
<TEXT>
Page 28


Exhibit 11

WESTAMERICA BANCORPORATION
Computation of Earnings Per Share on Common and
Common Equivalent Shares and on Common Shares
Assuming Full Dilution

<TABLE>
<CAPTION>

                                                               For the                  For the
                                                            three months               six months
                                                           ended June 30,            ended June 30,
                                                     ----------------------------------------------------
    (In thousands, except per share data)                2004         2003         2004         2003
                                                     ----------------------------------------------------
<S>                                                       <C>          <C>          <C>          <C>
    Weighted average number of common
      shares outstanding - basic                           31,760       33,000       31,906       33,054

    Add exercise of options reduced by the
      number of shares that could have been
      purchased with the proceeds of such
      exercise                                                583          492          596          474
                                                     ----------------------------------------------------
    Weighted average number of common
      shares outstanding - diluted                         32,343       33,492       32,502       33,528
                                                     ====================================================

    Net income                                            $24,644      $23,671      $48,958      $46,683

    Basic earnings per share                                $0.78        $0.72        $1.53        $1.41

    Diluted earnings per share                              $0.76        $0.71        $1.51        $1.39

</TABLE>


</TEXT>
</DOCUMENT>
