Background: Long-term results of percutaneous coronary intervention (PCI) for unprotected left main coronary artery (ULMCA) stenosis are limited. Methods: From June 1996 to May 2002, 56 consecutive patients (63 stents) with ULMCA stenosis (ostium 24, body 19, distal bifurcation 13) were followed up longer than one year. Primary endpoint was to evaluate long-term cumulative major adverse cardiac events (MACE). Secondary endpoint was 6 month angiographic restenosis rate (RS). Results: The procedural success rate was 100%. During 36 짹 22 months follow up, there were 3 deaths (2 cardiac, 1 non-cardiac, 5.4%), 1 non-fatal myocardial infarction and 12 target lesion revascularization (TLR) (21.4 %), including 8 CABG and 4 repeated PCI (cumulative MACE-free survival rate; 73.2%). The TLR had a different tendency by lesion location (ostium; 6/24, 25%, body; 2/19, 11%, distal bifurcation; 6/13, 46%, p= 0.07). Six month RS was 43.2% (16/37). The only determinant for MACE-free survival was post-minimal luminal diameter (MLD) (p=0.012), The instent-restenosis (ISR) rate at distal bifurcation (8/11, 72.7%) was significantly high compared to non-bifurcation sites (ostium and body, 8/26, 30.8%) (p=0.02). Conclusions: Coronary stenting for ULMCA stenosis was feasible, safe and showed favorable long-term MACE-free survival rate. Lagrer post-MLD following ULMCA stenting showed a salutary effect for MACE free survival up to 3 years. Bifurcation lesion had a high ISR rate, so other strategies like aggressive debulking or drug eluting stents may be needed for distal bifurcation left main stenotic lesions.