EXHIBIT 11 FIRST KEYSTONE CORPORATION COMPUTATION OF EARNINGS PER COMMON SHARE For the Nine Month Period Ended September 30, 1998 1997 (Dollars in Thousands) Primary Net Income $ 3,658 $ 3,455 Shares<F1> Weighted average number of common shares outstanding 2,931,648 2,933,727 Adjustments - increases or decreases None None Weighted average number of common shares outstanding as adjusted 2,931,648 2,933,727 Primary earnings per common share $ 1.25 $ 1.18 Assuming full dilution Net Income $ 3,658 $ 3,455 Shares<F1> Weighted average number of common shares outstanding 2,931,746 2,933,727 Adjustments - increases or decreases None None Weighted average number of common shares outstanding as adjusted 2,931,746 2,933,727 Earnings per common share assuming full dilution $ 1.25 $ 1.18 <FN> <F1> Restated to reflect a 3 for 1 stock split issued in the form of a 200% stock dividend paid in 1998. </FN> 18