Background: Although sirolimus-eluting stent(SES) has markedly reduced the risk of restenosis, small vessel disease remains a major cause of SES failure. We investigated predictive factors for cardiac events and restenosis after SES implantation in small coronary arteries. Methods and Results: A total of 1092 consecutive patients who received SES implantation (1269 lesions) for small vessel disease (���2.8mm) were included. All data were prospectively recorded, and follow-up angiography at 6 months was obtained at 751 patients (follow-up rate 70.3%, 889 lesions). Restenosis (diameter stenosis ���50%) was angiographically documented in 65 patients with 77 lesions (8.7%): 55 focal (71.4%), 8 diffuse (10.4%), 2 diffuse proliferative (2.6%) and 12 total (15.6%). Lesion length, stent length, and in-stent restenotic lesion were univariate predictors of restenosis. In multivariate analysis, however, lesion length (OR 1.046; 95%CI 1.018-1.075; p=0.001) and in-stent restenotic lesion (OR 2.277; 95%CI 1.071-4.842; p=0.032) were significant independent predictors of restenosis. During follow-up (23.2짹7.9 months), there were 17 deaths (5 cardiac, 12 noncardiac), 5 nonfatal myocardial infarction and 42 target lesion revascularizations. The cumulative probability of survival without major adverse cardiac events was 96.6짹0.6% and 95.1짹0.7% at 1 and 2 years, respectively. In multivariate analysis, lesion length (HR 1.039; 95%CI 1.012-1.066; p=0.004) and in-stent restenotic lesion (HR 3.292; 95%CI 1.580-6.858; p=0.001) were significantly related to major adverse cardiac events. Conclusions: Sirolimus-eluting stent implantation in small coronary arteries is safe and effective, with lesion length having a major impact on restenosis and major adverse cardiac events.