AIM AND OBJECTIVES; To study the prevalence and hospital outcome of metabolic syndrome (MS) and to assess each components of ATPIII definition of metabolic syndrome in patients with acute ST elevation myocardial infarction (STEMI). MATERIALS AND METHODS; 85 patients admitted with acute myocardial infarction in ICCU of CSI Rainy multispeciality hospital were taken.They are examined and investigated. Metabolic syndrome was defined according to the AHA/NHLBI statement maintaining NCEP–ATPIII criteria with minor modifications. Patient was diagnosed metabolic syndrome if they had any 3 of the following criteria. 1. Abdominal obesity (Waist circumference(WC) > 90cm in men, > 80 cm in women) 2. Low HDL level (< 40 mg/dl in men, <50mg/dl in women) 3. High blood pressure (BP>130/85 mmHg) 4. Fasting blood sugar(FBS) > 100mg/dl. 5. Triglycerides(TGL)–>150 mg/dl The heart failure was defined as the highest killip class reached during hospitalization. Patients were divided into two groups– with and without metabolic syndrome. The relative influence of MS with respect to hospital outcomes and various parameters like ventricular tachycardia, heart failure, duration of stay in ICU, recurrent MI, death were studied. RESULTS; In total of 85 patients with acute STEMI 49% of them fulfilled the criteria of metabolic syndrome.The MS is high in the age group of 50–69 years. The females 80% of them have metabolic syndrome.The components of metabolic syndrome WC, BP,FBS,TGL were increased,HDLwas decreased in metabolic syndrome group with acute STEMI. Severe heart failure (killip class >=2) were more prevalent in metabolic syndrome group (78.4%, P=0.001). The mean ICU stay in the metabolic syndrome group was high (1.8 days, P= 0.001). Conclusion; The prevalence of metabolic syndrome is high in acute myocardial infarction patients especially in women. The all 5 components of ATP III definition of metabolic syndrome showed strong association with myocardial infarction. Patients with metabolic syndrome have high incidence of adverse hospital outcomes such as heart failure.