Backgroud Stent thrombosis(ST) remains as a major cause of death and morbidity after drug eluting stent(DES) implantation. ST can occur acute, subacute, or late after stent implantation. The window of thrombotic risk have been extends far beyond that for BMS, even after years. So we investigated the clinical characteristics of stent thrombosis in according to time period. Methods This was a multi-center study, where we collected data of consecutive ST patients who underwent DES implantation from May, 2004, through April, 2006 at 10 centers. All information were sent to a core center and the clinical, angiographic and procedural characteristics of ST patients were analysed. Possible ST as well as angiographically proven ST were defined as ST in this study. In this study, the acute and subacute ST were categorized as early ST whereas late ST occurring after 6 month were defined as very late ST. Results During the study period, a total of 93 patients had 96 cases of ST(Cypher: 51(53%), TAXUS: 45(47%)). 58 cases were occurred early (< 30 days), 13 cases late(30-180days) and 25 cases very late (>180 days) after DES implantation. Early ST patients were older than late and very late ST patients(63짹11 vs. 56짹11 vs. 55짹10 p=0.004). There was no difference in diagnosis at the time of index procedure. Early ST were more frequently presented as cardiogenic shock (36% vs 15% vs 4%, p=0.006) but acute myocardial infarction presentation of ST was not different in according to time period (71% vs 46% vs 60%, p=0.205). ST of Cypher stents showed statistical insignificant preponderance for the early period while that of TAXUS stents showed preponderance for the late period(p=0.144). Early ST patients had heavy vascular calcification(20% vs 0% vs 0%, p=0.018) and more small post-intervention minimal luminal diameter (2.54mm vs 2.73mm vs 2.79mm, p=0.046). Type I bifurcation were more frequent in very late ST but did not reached statistical significance (35% vs 39% vs 62%, p=0.075). Case fatality was not different (22% vs 23% vs 8%, p=0.287). Conclusion Characteristics of STs were different in according to time period. Different pathophysiologic base may underlie to STs of different time period.