In this study, 1884 patients who were selected from 3647 consecutive patients who survived at least 6 days after an acute myocardial infarction were randomized to double-blind treatment with either placebo or timolol and followed for 12-33 months. One hundred fifty-two patients in the placebo group and 98 in the timolol group died. The life-table cumulative probability of total death was 21.9% in the placebo group and 13.3% in the timolol group, corresponding to a relative reduction of 39.4% (p = 0.0003). One hundred thirty-one nonfatal reinfarctions were confirmed in the placebo group and 90 were confirmed in the timolol group, including events among withdrawn patients. The life-table probability rate of reinfarction was 16.4% in the placebo and 11.8% in the timolol group (p = 0.001). We conclude that chronic treatment with timolol in survivors of acute myocardial infarction who can tolerate beta-adrenergic blockade is effective in reducing both total mortality and reinfarction over 33 months.