The prevalence of metabolic syndrome (MetS) is increasing worldwide and patients with MetS have increased risk of cardiovascular events. Recent studies in different populations showed higher prevalences of MetS in patients with acute myocardial infarction (MI) and identified MetS as an independent predictor of future cardiac events. This study sought to determine the prevalence of MetS in patients with acute MI and investigate the impact of MetS on adverse cardiovascular events after acute MI. One hundred and eighty-eight patients (155 men, 33 women) admitted with first acute MI were enrolled into the study. Of the total patients, 80 (42.6%) patients were diagnosed with MetS according to the National Cholesterol Education Program Adult Treatment Panel III criteria with modifications for high blood pressure and high fasting plasma glucose. Kaplan-Meier curves showed that the cumulative event-free survival rates did not differ between the patients with and without MetS during a median follow-up period of 27.7 (min:14, max:42) months (P>0.05). On multivariate Cox regression analysis controlling for hypertension, diabetes mellitus, glucose, MetS, and waist-to-hip ratio, there was no association between the major adverse coronary events and the presence of MetS (P>0.05), whereas Killip class (relative risk: 2.853, 95% confidence interval: 1.606-5.070; P<0.001) was identified as the only independent predictor of long-term cardiovascular outcomes. This study shows that MetS has no effect on long-term prognosis after MI. However, Killip class was identified as an independent predictor of major cardiac events. Coron Artery Dis 20:370-375 (C) 2009 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.