Résumé : A secondary subgroup analysis of the European Stroke Prevention Study of the effect of antiplatelet medication on the risk of myocardial infarction. —A randomized, double-blind, placebo-controlled study with two parallel treatment groups (dipyridamole plus aspirin and placebo). Sixteen centers from six countries participated in the study. —A total of 2500 patients who had had one or more transient ischemic attacks or cerebral infarctions participated. —Combination therapy with dipyridamole (75 mg three times a day) and aspirin (330 mg three times a day) was compared with placebo during 24 months' follow-up. —Prevention of fatal and nonfatal myocardial infarction. —A total of 105 myocardial infarctions occurred in the intention-to-treat analysis and 76 occurred in the explanatory analysis. The overall risk reduction of myocardial infarction with the study drugs was approximately 40% in both statistical analyses, but the result was statistically significant only in the intention-to-treat analysis. Therapeutic efficacy was better among male patients, patients younger than 65 years, and patients with hypertension. —Combination therapy with dipyridamole and aspirin reduces not only the risk of cerebrovascular ischemic events but also the risk of myocardial infarction. © 1993 Arch Neurol. All rights reserved.