1 EXHIBIT 11.1 GENOME THERAPEUTICS CORP. AND SUBSIDIARIES CALCULATION OF SHARES USED IN DETERMINING PRIMARY NET INCOME (LOSS) PER SHARE YEAR ENDED AUGUST 31, ------------------------------------------ 1993 1994 1995 ---------- ---------- ---------- Weighted average common stock outstanding during the year .............................................. 10,668,628 11,097,224 12,287,918 Weighted average common stock equivalents outstanding during the year ................................... -- -- 673,816 ---------- ---------- ---------- 10,668,628 11,097,224 12,961,734 ========== ========== ========== CALCULATION OF SHARES USED IN DETERMINING FULLY DILUTED NET INCOME (LOSS) PER SHARE YEAR ENDED AUGUST 31, ------------------------------------------ 1993 1994 1995 ---------- ---------- ---------- Weighted average common stock outstanding during the year .............................................. 10,668,628 11,097,224 12,287,918 Weighted average common stock equivalents outstanding during the year ................................... -- -- 748,823 ---------- ---------- ---------- 10,668,628 11,097,224 13,036,741 ========== ========== ==========