Background: The long-term clinical outcomes after percutaneous coronary intervention (PCI) versus coronary artery bypass grafting (CABG) has not been known in patients with non-bifurcation (ostium and shaft) lesions of unprotected left main coronary artery (ULMCA). Methods: Between Jan, 2000 and June, 2006, a total of 1090 patients with ostium and shaft ULMCA stenosis were collected from 12 academic institutions in Korea. Percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) were performed in 577 patients and 513 patients, respectively. Results: Compared to patients with PCI, patients with CABG were significantly older and showed a higher incidence of previous myocardial infarction (MI), peripheral vascular disease, hyperlipidemia, poor LV function (LVEF<40%), and high Euroscore (���6) and more presented with acute coronary syndrome. The mean follow-up period was 900.8604.7 days in patients with underwent PCI and 900.8604.7 days in patients with underwent CABG. There was no difference of death or Q-wave myocardial infarction between PCI and CABG group. However, patients with PCI showed a significantly higher incidence of target vessel revascularization than those with CABG. This trend was persistent in comparison between drug-eluting stents and CABG (Table). Conclusions: There was no difference in death or Q-MI in patients with ostial and shaft ULMCA disease with regard to PCI and CABG. However, percutaneous revascularization without regard to stent type was significantly associated with target vessel revascularization than bypass surgery.