Background Although drug-eluting stents (DES) have dramatically reduced the rate of restenosis, concerns have been raised regarding the risk of stent thrombosis (ST) with the unrestricted use of these stents.Therefore, we investigated the clinical characteristics, predictors, and outcomes of ST after successful DES implantation in Koreans. Method This was a multicenter study, where we collected data of consecutive ST patients who underwent DES implantation from May, 2004, through May, 2007 at 10 medical centers. All information were sent to a core center and characteristics of ST patients were compared with a control group of 3,764 patients in a core center who had up to 6 months of clinical follow-up. ST cases were determined as Academic Research Consortium definition. Acute and subacute ST cases were defined as early ST. Results During the study period, a total of 127 patients had 131 cases of ST(Cypher:74(57%), TAXUS: 56(43%)). ST occurred acutely in 6 cases (5%), subacutely(���30 days) in 69(53%), late(30-365 days) in 31(24%) and very lately(>365 days) in 25(19%). The definite ST cases were 117(91%), probable 9(7%) and possible 3(2%). The mean duration to ST from the stent implantation was 5.8짹5.1 days in early and 383짹288 days in late ST. At the time of ST, dual antiplatelet therapy was being taken by 96% in early and 35% in late ST patients (p<0.0001). The cardiogenic shock has occurred in 24(34%) among early and 8(14%) late ST cases(p=0.013). Ninety seven(74%) ST patients were treated with percutaneous coronary intervention and 10(8%), with CABG. Among the 127 patients, 21 died (case fatality rate 17%). By multivariate analysis, independent predictors of ST were bifurcating lesion(OR 6.1;95% CI 3.01-9.52), initial diagnosis of AMI(OR 3.48;95% CI 2.3-5.26), small stent diameter(OR per 1mm decrease 2.13;95% CI 1.12-4.08), multivessel disease (MVD)(OR 1.83;95% CI 1.19-2.82), young age(OR per year decrease 1.03; 95% CI 1.01-2.14) and hypertension(OR 0.625; 95% CI 0.41-0.95). Conclusions In a study involving 10 centers in Korea, nearly half of the ST cases occurred in the late period. Bifurcating lesion, AMI, MVD, young age, lower blood pressure and small stent diameter were identified as predictors of ST.