Background: Although smoking is an important conventional risk factor of coronary artery disease, but it is unclear whether the quit smoking (>1Years) can reduce major clinical events in patients (pts) undergoing percutaneous coronary intervention (PCI) with drug-eluting stents (DESs) as compared with current smoker. Methods: The study population consisted of 730 pts who had history of smoking and underwent PCI with DESs enrolled from January 2004 to December 2008. Ex-smoker was defined as quit smoking more than one-year before admission (n=247, 33.8%). A current smoker was defined as smoking within 1 month before admission (n=483, 66.2%). Twelve-month cumulative clinical outcomes were compared between the two groups. Results: A total 700 pts (96%) were finished 12-month clinical follow up. The baseline clinical and procedural characteristics were similar between the two groups except that current smoker were younger (60.53짹10.82 vs. 66.21짹10.81 years, p<0.001), more acute myocardial infarction (AMI, 40.0% vs. 24.0%, p<0.001), and higher triglyceride (152.82짹104.32 vs. 129.36짹76.25, p=0.002). At 12 months, repeat PCI including target lesion and vessel revascularization (TLR & TVR), TLR-major adverse cardiac events (MACE), TVR-MACE were lower in the current smoker group in univariate analysis (Table). However, after baseline adjustment by multivariate analysis, Ex smoker was not an independent predictor of repeat PCI (OR 0.634, 95% CI 0.370-1.086, p=0.097), TLR-MACE (OR 1.632, 95% CI 0.913-2.916, p=0.098) and TVR-MACE (OR 1.465, 95% CI 0.885-2.431, p=0.139). Conclusions: Pts in Ex Smoker group failed to show its clear association with better mid-term clinical outcomes as compared with those of pts in current smoker group. More prolonged abstinence from smoking might be needed to achieve significant cardiovascular risk reduction.