Background: It has been known that ischemic stroke (IS) is a major complication of atrial fibrillation (AF). We investigated the risk factors for IS in patients with AF by retrospective analyses of age and sex matched patient groups. Methods: Among 88 patients with AF (44 males, 63짹9 years old, 62.5% persistent AF and 37.5% paroxysmal AF), we compared the clinical parameters in patients with AF and IS (IS group: n=44) and those without IS (CONT group; n=44). We estimated the effectiveness of rhythm control by no awareness of symptom and sinus rhythm on follow-up electrocardiography (ECG). Results: 1. Proportions of persistent AF were 68% and 57% in IS group and CONT group, respectively (P=NS). 2. IS group had higher systolic (136짹20 vs. 123짹17 mmHg, P<0.01) and diastolic blood pressures (85짹14 vs. 76짹10 mmHg, P<0.01), lower INR (1.2짹0.3 vs. 1.5짹0.7, P<0.01), lower HDL cholesterol (46.6짹12.3 vs. 54.0짹18.3 mg/dL, P<0.05), and lower use of warfarin (32% vs. 75%, P<0.001) or AAD (16% vs. 80%, P<0.001) than CONT group. 3. Independent predictors of IS were INR < 2.0 (HR 15.4; 1.69-139.61, P<0.05) and high diastolic blood pressure (HR 1.1; 1.01-1.10, P<0.05). 4. SR was maintained in 32% (14/44) of IS group and 64% (28/44) of CONT group (P<0.01), respectively. The maintenance of SR (HR 0.3; 0.10-0.73, P<0.001) was an independent negative predictor for IS. 5. The frequency of diabetes, smoking, coronary artery disease, and left atrial size or ejection fraction did not affect the incidence of IS in patients with AF. Conclusion: Appropriate anticoagulation and normal lipid profile, blood pressure control, and optimal rhythm control are important predictors preventing IS in both patients with paroxysmal and persistent AF.