Background: The risk of late thrombosis after drug eluting stents implantation has been an increased concern, especially when the antiplatelet therapy is interrupted. The late thrombosis of coronary stent may have several different mechanism such as the inflammatory reaction or malapposition of stent. In this study, we evaluated the predictors of stent thrombosis(ST) after implantation of drug-eluting stent (DES) in routine clinical practice. Method: The study population comprised 914 patients (1132 lesions) with follow-up angiography from May 2006 to April 2009, who were successfully treated with percutaneous coronary intervention (PCI) with DES or BMS stent before. Stent thrombosis was defined by ARC definitions as definite or probable and was categorized as acute (<24 hrs after stent implantation), subacute (1-30 days), late (1-12 months), or very late(>12months). We selected definite ST patients. Clinical characteristics, coronary risk factors, lesion characteristics and procedure types were evaluated in ST and non ST groups. Result: Of 743 patients(53.6% males and aged 62.99짹10.7years) treated with drug-eluting stent, 18 patients (2.3%) (males 13 and aged 55.1짹11.5years) presented with a definite ST(acute in 2, subacute in 11, late in 4 and very late in 1.). Patients with ST were implanted SES in 4, PES in 11, ZES in 2 and EES in 1. The differences between both groups were showed below as. In multivariate logistic regression analysis, longer stent length (HR 1.066, p=0.038), higher Lp(a) level (HR 1.029, p=0.025), higher CRP level (HR 1.925, p=0.035) and acute coronary syndrome at initial presentation (HR 20.998, p=0.007) were the independent predictors associated with ST. Conclusion: The incidence of ST were higher as expected. Stent length, CRP level, Lp(a) level and acute coronary syndrome at initial presentation might be predictors of ST. However, larger and long term study might be needed.