Objective: This cross-sectional, observational study investigated prevalence and clinical features of atrial fibrillation (AF) in diabetic patient groups with or without autonomic neuropathy. Methods: One hundred and fourteen consecutive patients with pharmacologically treated type-II diabetes mellitus were enrolled for this study in our institution between January 2010 and December 2010. All patients underwent 12-lead electrocardiography on the day of enrollment for AF detection. All diabetic patients underwent neurologic examination for the presence of diabetic autonomic neuropathy (DAN). Following clinical evaluation, sympathetic skin responses (SSR) and RR interval variability (RRIV) analysis were used for the detection of autonomic neurologic involvement. Patients were divided into two groups according to presence (Group 1) or absence (Group 2) of DAN. Patient groups with or without DAN were compared for AF occurrence. Continuous and categorical data were compared with independent samples t- test and Chi-square statistical tests respectively. Results: Atrial fibrillation prevalence was 24% (n=29) in study population. Diabetic autonomic neuropathy was diagnosed in 47 (39%) patients. Basal characteristics of patients with or without DAN were comparable except glycosylated hemoglobin A (HbA1c) levels. HbA1c levels were found significantly higher in patients with DAN. Atrial fibrillation was diagnosed in 14 patients in Group 1 and in 15 patients in Group 2. Significantly increased AF prevalence (31.9% vs. 20.8%, p=0.014, in groups with and without DAN respectively) was observed in patient group with diabetic autonomic neuropathy. Conclusion: The results of this study demonstrated an increased prevalence of AF in patients with diabetic autonomic neuropathy compared with non-neuropathic, diabetic patients. Further investigation of this relation with prospective studies is needed to demonstrate a causal relationship between diabetic autonomic neuropathy and AF.