Exhibit 11 ENGINEERED SUPPORT SYSTEMS, INC. STATEMENT RE: COMPUTATION OF EARNINGS PER SHARE Three Months Ended January 31 ---------------------------- 2000 1999 ---------- ---------- NET INCOME $2,574,169 $1,388,403 ========== ========== BASIC EARNINGS PER SHARE Average basic shares outstanding 6,928,043 4,852,342 ========== ========== $.37 $.29 ========== ========== DILUTED EARNINGS PER SHARE Average basic shares outstanding 6,928,043 4,852,342 Net effect of dilutive stock options<F1> 150,158 179,997 ---------- ---------- 7,078,201 5,032,339 ========== ========== $.36 $.28 ========== ========== <FN> <F1> Based on the treasury stock method. 15