In an observational prospective study of 1,410 patients (mean age, 81 +/- 9 years) with prior myocardial infarction, no contraindications to aspirin, and a serum low-density lipoprotein cholesterol level of 125 mg/dL or higher, 832 (59%) were treated with aspirin. At the 36-month follow-up evaluation, the incidence of new coronary events was 52% in persons treated with aspirin versus 70% in those who were not treated with aspirin (P < 0.0001). The stepwise Cox regression model showed that significant independent predictors of new coronary events were age (risk ratio, 1.05 for each 1-year increase), current cigarette smoking (risk ratio, 2.7), hypertension (risk ratio, 1.7), diabetes mellitus (risk ratio, 2.2), initial serum low-density lipoprotein cholesterol level (risk ratio, 1.01 for each 1-mg/dL increase), initial serum high-density lipoprotein cholesterol level (risk ratio, 0.96 for each 1-mg/dL increase), use of statins (risk ratio, 0.46), and use of aspirin (risk ratio, 0.48).