Background: Stent thrombosis (ST) continues to be an important complication of contemporary DES use. However, the pathophysiology of ST after Drug-eluting stent (DES) implantation has not been fully elucidated. The aim of this study is to assess the characteristics of acute and subacute ST after coronary intervention with DES. Methods: From a total cohort of 1760 consecutive patients (2257 lesions) who underwent coronary intervention since April 2003 to June 2006, acute or subacute ST occurred in 11 patients (0.49%). Among them, nine patients (8 male, age 68짹16) with DES implantation were analyzed. Results: Seven patients (0.37%) had subacute ST, which were developed at 7.9 days (3-18 days) after intervention. Five patients were developed in infarction related artery, but just two cases were primary intervention. They had lower ejection fraction than 40%. Two patients were underwent multiple stents implantation. Most of them (8 patients) had complex lesions. Especially, 4 cases were heavy calcified lesion, and 2 cases were CTO intervention. Taxus was deployed in 6 cases. Three patients showed suboptimal results after intervention: two stent under-expansion related to severe calcification, one residual distal lesion related to thrombi. Except one case, they had adequate antiplatelet therapy (more then dual therapy). Conclusions: Despite small number of cases, most of acute and subacute ST had the relation with lesion complexity. Careful management is warranted in the patients with complex lesions, also in infarct related artery. For the prediction of ST, further investigation should be needed.