Objectives: The aim of this study was to evaluate long-term (5-year) clinical outcomes after percutaneous or surgical revascularization in diabetic population with unprotected left main coronary artery (LMCA) disease. Background: Limited information is available on long-term comparative outcomes for diabetic patients with unprotected LMCA disease who underwent stent implantation or coronary artery bypass grafting (CABG). Method: A total of 722 diabetic patients with unprotected LMCA stenosis who underwent stenting (n=327) or CABG (n=395) were examined. After baseline risk factors adjustments, the 5-year adverse outcomes (death; a composite outcome of death, Q-wave MI or stroke; target-vessel revascularization [TVR]; and definite stent thrombosis [ST]) between the two groups were compared. Results : After adjustment of covariates, the 5-year risk of death (hazard ratio [HR], 0.814, 95% confidence interval [CI], 0.546-1.215, p=0.314), the combined risk of death, Q-wave MI, or stroke (HR, 0.788, 95% CI, 0.531-1.169, p=0.237) and the risk of ST (p=0.361) were not significantly different. However, the risk of TVR was significantly higher in the stenting group than in the CABG group (HR, 4.538, 95% CI, 2.615 – 7.875, p<0.001). (Table) Conclusion: During long-term (5-year) follow-up, coronary stenting showed similar rates of mortality and of the composite of death, Q-wave MI, or stroke, but higher rates of TVR as compared with CABG for diabetic population with unprotected LMCA disease.