Background: Atrial fibrillation (AF) is a common complication in elderly patients with atrial septal defect (ASD). The purpose of this study was to examine the efficacy of the maze procedure in these patients. Materials and Methods: Between February 2000 and May 2011, 46 patients underwent the maze procedure as a concomitant operation with ASD closure. Three patients who underwent a right-sided maze were excluded, and one patient was lost to follow-up. The mean follow-up duration was $3.2{pm}2.5$ years. Electrocardiography was performed 1 month, 3 months, 6 months, and 1 year after surgery, and checked annually after that. Results: AF persisted in 4 patients after surgery. One year after surgery, among 38 patients, 55.3% remained in sinus rhythm without antiarrhythmic drugs. However, when including the patients who took antiarrhythmic drugs, 92.1% were in sinus rhythm. Freedom from AF recurrence at 3 months, 6 months, 1 year, 2 years, 3 years, and 5 years after surgery were $97.4{pm}2.6$, $94.4{pm}3.8$, $91.2{pm}4.9$, $87.8{pm}5.8$, $79.5{pm}7.6$, and $68.2{pm}12.4$, respectively. There was no early mortality after operation. Conclusion: Concomitant treatment with the maze procedure and ASD closure is safe and effective for restoring the sinus rhythm.