Exhibit 11

WESTAMERICA BANCORPORATION

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

	2002		2001		2000
	(In thousands, except per share data)
Weighted average number of common shares outstanding — basic		33,686		35,213		36,410
Add exercise of options reduced by the number of shares that could have been purchased with the proceeds of such exercise		539		535		526
Weighted average number of common shares outstanding — diluted		34,225		35,748		36,936
Net income	$	87,138	$	84,279	$	79,779
Basic earnings per share	$	2.59	$	2.39	$	2.19
Diluted earnings per share		2.55		2.36		2.16