Introduction: Stent thrombosis (ST) is a devastating complication in the Drug Eluting Stent (DES) era. We investigated the incidence, clinical characteristics of ST and its relation to aspirin resistance of the patients (pts) with ST in an Asian population. Methods: We retrospectively analyzed 614 pts (278 males, 63.12짹10.89yrs) who received DES from June 2004 to April 2006 in our unrestricted single center DES registry. ST was defined as acute (<24 hrs), subacute (>24hrs till 30 days), late (>30 days till 6 months) and very late (>6months). At 6-month angiographic follow up, platelet function test was routinely performed by Chrono-log Aggregometers (model 490). The aspirin resistance was defined as 5 關mol/l adenosine diphosphate (ADP)-induced aggregation of ���70%, and 0.5 mg/ml arachidonic acid-induced aggregation of ��� 20%. Results: The incidence of ST was 1.1% (7/614).The conventional coronary risk factors were not different with control study population. Among the 7 ST patients (6 Males, Ages 58짹14.32 yrs), 4 (0.65%) were documented on angiogram and 3 (0.48%) were highly suspicious of ST from the clinical event. There were 3 acute, 2 subacute, 2 late and none very late ST pts. The 13 Paclitaxel and 4 Sirolimus DES (length 21.23짹4.94 mm, diameter 2.57짹0.38 mm) were deployed to cover 9 left anterior descending (LAD), 2 left main, 2 left circumflex (LCX) lesions. Type C lesion was in 69%. None of the pts received Glycoprotein GP IIbIIIa blocker. All pts were on dual antiplatelet therapy. Angiographically proven 4 pts underwent platelet function assay and none of the pts had documented aspirin resistance. During the clinical follow up, 4 pts died, 1 had Q-wave myocardial infarction (MI) and 3 required repeat revascularization. Conclusion: The overall incidence of ST in an Asian DES registry was 1.1% and showed very worse clinical outcomes. The lesions were complex although the lengths were not very long to predispose for ST. All pts were on the dual antiplatelet regimen and no other specific influencing risk factors. Furthermore, the hypersensitivity to DES polymer and the role of aspirin and/or clopidogrel resistance should be investigated in the Asian context.