Background: There is little evidence on the optimal antithrombotic therapy following percutaneous coronary intervention (PCI) in patients with atrial fibrillation (AF). We aimed to investigate the outcomes in relation to antithrombotic treatment strategies after PCI in patients with AF. Methods: We performed retrospective analysis of 121 patients (67.8% men, mean age 68.3 짹 7.8 years) with AF who had undergone PCI with stent implantation between 2005 and 2007. We reviewed clinical, demographic and procedural characteristics. Stroke risk factor and antithrombotic regimens were also analyzed. Primary end point was defined as major adverse cardiac events (MACE) which include death, myocardial infarction, target vessel revascularization and stent thrombosis. Clinical events such as stroke, major or minor bleeding were also evaluated. Results: Accompanying comorbidities were as follows; hypertension (59.5%), diabetes (37.2%) congestive heart failure (16.5%). The average number of stroke risk factor was 1.6. At the time of discharge, warfarin was prescribed in 28 patients (23.1%). Mean follow-up period was 523 짹 324 days. The incidence of all adverse events, MACE, stroke and major bleeding was 21.5%, 9.9%, 3.3% and 4.1%, respectively. All cause mortality was 7.4%. In Kaplan-Meier survival analysis, warfarin treatment was not associated with lower risk of MACE (p = 0.601) or mortality (p = 0.324). However, it was associated with increased risk of major bleeding (p = 0.011). Cox regression analysis showed that independent predictor of MACE was diabetes (p = 0.024). Conclusion: It is likely that the benefit of oral anticoagulation therapy after PCI in Korean AF patients is different from that in western population.