Background: Only few data have been reported with regard to primary percutaneous coronary intervention (PCI) with drug-eluting stent (DES) for acute AMI due to left main coronary artery occlusion (LMCO). The aim of this study is to investigate the incidence of LMCO in acute myocardial infarction, the efficacy of primary PCI for LMCO with DES, and to evaluate the clinical features, outcome, and prognostic determinants. Methods: On-line registry of AMI at the web site has been performed in 41 primary PCI centers in Korea (KAMIR). From November 2005 to May 2007 of 10,740 patients with AMI treated in each PCI center are registered. In this registry, 51 patients (M:F = 42:10, 64.9짹10.0 years) of 10,740 patients had a total or subtotal acute LMCO (0.47%). The clinical features of 51 patients and in-hospital mortality are analyzed. Result: Of 51 patients, 36 underwent PCI which had a success rate of 93%; an optimal angiographic result was achieved in 84%. Stent implantation was performed in 29 patients. Of the 29 stent implantation, 25 patients were DES (Cypher: 11, TAXUS: 11, Endeavor: 4). 12 patients underwent CABG. The in-hospital mortality was developed in 17(33.3%) patients. The main cause of death was pump failure, combined with cardiogenic shocks. There were no significant difference in mortality between emergent CABG and PCI (31.3% vs 34.3%, p>0.05), among different DESs. Multivariate analysis showed that initial Killip class were significantly related to in-hospital mortality [Odd ratio: 4.46, 95% CI: 1.28-15.61, p=0.02]. Conclusion: In-hospital mortality in patients with acute myocardial infarction due to LMCO still remains high, even with early interventional therapy and using DES. However, our data demonstrate that the PCI with DES in these high-risk patients is feasible with acceptable success rates. Therefore, in the case of LMCO, the primary PCI with stent is initially recommended for early revascularizations.