Cardiovascular disease (CVD), which includes myocardial infarction(MI), stroke, and peripheral vascular disease, remains the leading cause of death in the United States and in most developed countries. In the United States today, 25% of patients have metabolic syndrome-including those who have had a prior occlusive vascular disease event, those who are having an acute MI or ischemic stroke, and finally, the largest segment of the population,namely those who have not yet experienced a clinical CVD, but whose risks are substantial (10-year risk 10%). This article reviews the totality of evidence for aspirin in the treatment and prevention of CVD and emphasizes its importance as adjunctive therapy for patients with metabolic syndrome.