1 Exhibit 11 ENGINEERED SUPPORT SYSTEMS, INC. STATEMENT RE: COMPUTATION OF EARNINGS PER SHARE Three Months Ended January 31 ---------------------------- 1998 1997 ---------- ---------- NET INCOME $ 919,161 $ 802,831 ========== ========== BASIC EARNINGS PER SHARE Average shares outstanding 3,174,755 3,182,114 ========== ========== $.29 $.25 ========== ========== DILUTED EARNINGS PER SHARE Average shares outstanding 3,174,755 3,182,114 Net effect of dilutive stock options<F1> 136,822 127,842 ---------- ---------- 3,311,577 3,309,956 ========== ========== $.28 $.24 ========== ========== <FN> <F1> Based on the treasury stock method. 12