This study aimed to determine the effect of continuous positive airway pressure (CPAP) therapy on patients with atrial fibrillation (AF) and obstructive sleep apnea (OSA) after radiofrequency ablation (RFCA). OSA predicts recurrence of AF in patients with AF and OSA after RFCA. However, the effect of CPAP therapy on recurrence of AF in these patients after RFCA is poorly known. All 122 patients who underwent RFCA from 2017 to 2020 were diagnosed OSA by polysomnography. A total of 62 patients were treated by CPAP, while the remaining 60 were not treated by CPAP. The recurrence of atrial tachyarrhythmia and use of antiarrhythmic drugs were compared between the two groups during a follow-up of 12 months. The outcome of these patients with OSA was compared to a group of 60 AF patients under-going RFCA without OSA. Patients undergoing CPAP therapy had a higher AF-free survival rate compared to non-CPAP-treated pa-tients (70.3% versus 31.5%; P = 0.02). LAD was associated with the risk of AF recurrence in patients with OSA (HR per mm increase: 1.0; 95% CI: 1.06-1.21; P = 0.01). The CPAP nonusers had more than two-fold in-creased risk of AF recurrence following pulmonary vein isolation (HR: 2.37; 95% CI: 1.21-4.96; P = 0.02). CPAP treatment highly increased arrhythmia-free survival in AF patients accompanied by OSA after RFCA and reduced recurrence of AF in these patients.