Objectives Acute non-ST elevation myocardial infarction (NSTEMI) has different clinical presentation, treatment strategy, and prognosis compared with ST-elevation myocardial infarction (STEMI), but its clinical characteristics and prognosis are not well-defined in Korea. Methods From Nov 1st 2005 to Dec 31st 2008, 239 patients with AMI admitted to our hospital: 83 patients with NSTEMI (35%; 65.0짹13.1 yrs) and 156 patients with STEMI (65%; 62.8짹13.5 yrs). Results More patients with NSTEMI complained of atypical chest pain, and had previous angina, ischemic heart diseases and DM. Maximal serum CK-MB level was lower in NSTEMI group. Left ventricular ejection fraction and regional wall motion score index were not different. The major cardiovascular adverse event (MACE) rate at 1 month was greater in STEMI group (10.3% in STEMI and 4.8% in NSTEMI; p=0.16). Kaplan-Meier survival analysis showed the less 1 year mortality rate of NSTEMI group (4.8% vs. 11.5%; p=0.082), but 1 year event (death, MI, or repeated revascularization) rate was similar (20.5% vs. 21.2%) because of greater repeated revascularization in NSTEMI group. Conclusions Clinical manifestations were somewhat different between NSTEMI and STEMI groups. The mortality rate was lower in NSTEMI group, but the long-term event rate was not different.