Background: Recent foreign clinical trials reported sex differences of clinical outcome after acute myocardial infarction (AMI). But there is no data regarding the clinical differences after AMI in Korean. We therefore analyzed a database from a nationwide, prospective, multicenter, Korean Acute Myocardial Infarction Resistry (KAMIR) study of AMI to access the clinical features and it���s outcome of women compared with men. Method and Results: Between November 2005 to July 2006, 2408 patients who admitted with ST-segment elevated AMI were registered to KAMIR database. Of these patients, 679 (28%) were women and 1729 (72%) were men. Compared with men, women were significantly older (70짹9 years), had higher incidence of metabolic syndrome (54%), hypertension (53%) and dyslipidemia (40%). The time interval from the onset of chest pain to emergency room (ER) visit (5hr 53 min vs 5hr 39 min, P=0.432) was similar, but the rate of ER visit within 12 hours from initial chest pain (69% vs 77%, P<0.001) was higher in men. On ER visit, women showed higher incidence of cardiogenic shock though the infarct related artery and severity of coronary artery disease did not significantly differ between the sexes. On treatment, women got less frequently the urgent reperfusion therapy at ER (72% vs 76%, P=0.031). As the results, women showed higher in-hospital mortality than man (10% vs 4.1%, P<0.001). The major in-hospital outcomes were as below (table) Conclusions: We concluded that women have different cardiovascular risk profiles and were treated less invasively than men. Furthermore, women show higher in-hospital mortality than men.