Metabolic syndrome (MS) consists of a cluster of metabolic and hemodynamic disorders that promote the development of atherosclerosis and increase cardiovascular morbidity/mortality. We evaluated the prevalence and characteristics of MS after acute coronary syndrome (ACS) and the effect of intensive risk factor management on the morbidity/mortality associated with MS in a therapeutic cohort; 480 consecutive patients were summoned 3 months after an ACS for cardiovascular evaluation and management. Follow-up was carried out 16 months later. At 3 months after ACS, prevalence of MS was 20.8%, as assessed by criteria of the National Cholesterol Education Program Adult Treatment Panel III and 27.7% according to the definition of the International Diabetes Federation. The most common metabolic disorders were abdominal obesity, hypertriglyceridemia, and fasting hyperglycemia. Characteristics of the initial ACS showed no significant difference between the MS and non-MS groups. Atherosclerotic extent was greater in the MS group according to Adult Treatment Panel III. At follow-up, the MS and non-MS groups achieved optimal low-density lipoprotein cholesterol and blood pressure levels. During follow-up, there was an increase in total mortality in the MS group compared with the non-MS group (5.2% vs 1.4%, p <0.01) as assessed by International Diabetes Federation criteria; however, no difference in minor or major cardiovascular events was found between the 2 groups. In conclusion, MS was highly prevalent after an ACS, notably in young patients, and was not associated with a specific ACS presentation.