Background: A sirolimus-eluting stent (SES) (Cypher, Cordis Corp) has been reported to reduce in-stent restenosis in several clinical trials with selected lesion and patient subsets. However, relatively few data on the efficacy of SES for reduction of in-stent restenosis and its safety in various lesions of real world practice are currently available. Methods: A multicenter cohort of consecutive patients treated with SES during the period of April, 2003 ~ May, 2004 included 769 patients (age 61.1짹10.6 years, female 31.7%) with 948 lesions. Clinical outcomes and angiographical follow-up data at 6 months were investigated. Results: The baseline lesion length was 22.6짹11.4 mm, reference diameter 2.8짹0.5 mm and minimal luminal diameter (MLD) 0.7짹1.0 mm. Post-stenting MLD was 2.7짹0.5 mm. The subsets of stented lesions were DM (n=353, 32.5%), chronic renal failure of end-stage renal failure (n=89, 8.2%), culprit lesion of acute myocardial infarction (MI) (n=114, 10.5%), long lesion > 30 mm (n=164, 17.3 %), small vessel <3 mm (n=347, 36.6%), left main (n=20, 2.1%), bifurcation (n=108, 9.9%), chronic total occlusion (n=49, 4.5%) and in-stent restenosis (n=45, 4.1%). Preliminary clinical and angiographical results are as follows: Major adverse cardiac events (death, MI, target vessel revascularization) occurred in 7(0.9%) patients (3 deaths, 4 MI) at 30 days and in 15(4.3%) patients at 6 months. Evident or suspected events of subacute thrombosis were noted in 6 (0.78%) patients. In-stent restenosis was documented in 5.1%. Follow-up MLD was 2.4짹0.6 mm and late loss 0.3짹0.6 mm. Final clinical and angiographic results will be presented at the scientific meeting. Conclusions: Despites various limitations of this study, SES showed reliable safety and excellent efficacy for reduction of in-stent restenosis rates in various lesion subsets of real world practice.