Background: The presence of atheroma or increase of intima-media thickness of thoracic aorta have been recognized as an independent risk factor for atrial fibrillation (AF). The aim of this study was to determine whether atherosclerotic burden of the thoracic aorta may affect the risk of AF recurrence after radiofrequency ablation. Methods: One hundred five patients who were undergone transesophageal echocardiography prior to ablation for paroxysmal or persistent AF were enrolled. We divided the patients into three groups: [group 1, all patients with AF (age = 58짹11 years, M:F=76:29); group 2, patients with paroxysmal AF (age = 58짹12 years, M:F = 37:19); group 3, patients with persistent AF (age = 58짹11 years, M:F=39:10)]. Each group was subdivided into two groups: (group without AF recurrence and group with AF recurrence). The relations between the AF recurrence and the variables including the atherosclerotic finding of aorta and other clinical factors were evaluated. Results: 1.In group 1 and 3, the presence of the aortic plaque showed significant association with the recurrence of AF and the degree of thickness of the aortic plaque did as well. 2. There were significant differences in left atrial(LA) volume and LA volume adjusted with body surface area between groups with and without recurrence, except in paroxysmal AF patients. Conclusions: The atherosclerotic burden of thoracic aorta and the LA size are related to the recurrence of AF. These findings may suggest that the underlying structural difference is important even in patients with same pattern of AF.