The aim of this study was to identify predictors for recurrent atrial fibrillation after internal and external cardioversion in 157 patients. After cardioversion, patients were treated orally with sotalol (174 +/- 54 mg/day). Univariate predictors for recurrence included coronary artery disease (p < 0.05) and advanced age (p < 0.05). Multivariate adjusted risk for relapse increased with the presence of coronary artery disease (odds ratio [OR] 3.4, 95% confidence interval [CI] 1.6 to 8.0), presence of atrial fibrillation > 2 months before cardioversion (OR 2.3; 95% CI 1.4 to 4.5), left atrial diameter > 60 mm (OR 2.1; 95% CI 1.2 to 3.1), and age > 65 years (OR 1.6; 95% CI 1.3 to 3.3). In 26% of patients with lone atrial fibrillation, recurrence was observed compared with 51% of patients with underlying structural heart disease (p < 0.05). The mode of conversion, internal or external, had no impact on the recurrence rate. These findings might be useful for selection of the most appropriate therapy for the individual patient.