BACKGROUND Randomized and controlled studies have reported the effect of catheter ablation (CA) for atrial fibrillation (AF) over a follow-up of 1224 months. OBJECTIVE We report on the effect of CA plus antiarrhythmic drugs in comparison with antiarrhythmic drugs alone on the maintenance of sinus rhythm over 12-year follow-up. METHODS We extended the follow-up duration of the 137 patients who were enrolled in the Catheter Ablation for the Cure of Atrial Fibrillation Study between February 1, 2002, and June 30, 2003, and randomized to antiarrhythmic drugs (control group) or antiarrhythmic drugs plus CA (ablation group). The primary end point was time to first symptomatic or asymptomatic recurrence of atrial arrhythmia lasting >30 seconds during follow-up. RESULTS During follow-up, 19 of 68 (27.9%; 95% confidence interval [CI] 18.7%39.6%) ablation group patients and 3 of 69 (4.3%; 95% CI 1.49%12.0%) control group patients did not experience any relapse of atrial tachyarrhythmia (P < .001). The Kaplan-Meier analysis performed to determine the probability of survival free from atrial arrhythmias showed a statistical difference in favor of the ablation group (log-rank, P < .001). The effect of CA was consistent in both patients with paroxysmal AF and those with persistent AF. In the multivariate Cox regression analysis, belonging to the control group (hazard ratio 2.95; 95% CI 1.8964.726; P < .001) and longer time since first AF episode (hazard ratio 1.004; 95% CI 1.0021.084; P = .041) were predictors of atrial tachyarrhythmia recurrence. CONCLUSION In patients with paroxysmal and persistent AF, CA significantly increased time to first recurrence of atrial arrhythmias during 12-year follow-up.