Background In patients with atrial fibrillation (AF), the addition of surgical ablation to aortic valve replacement (AVR) does not increase procedural morbidity or mortality. However, efficacy in this population has not been carefully evaluated. This study compared outcomes between patients undergoing stand-alone Cox-Maze IV with those undergoing surgical ablation and concomitant AVR. Methods From January 2002 to May 2014, 188 patients received a stand-alone Cox-Maze IV (n = 113) or surgical ablation with concomitant AVR (n = 75). In the concomitant AVR group, patients underwent Cox-Maze IV (n = 58), left-sided Cox-Maze IV (n = 3), or pulmonary vein isolation (n = 14). Thirty-one perioperative variables were compared. Freedoms from AF on and off antiarrhythmic drugs were evaluated at 3, 6, 12, and 24 months. Results Follow-up was available in 97% of patients. Freedom from AF on and off antiarrhythmic drugs in patients receiving a stand-alone Cox-Maze IV versus concomitant AVR was not significantly different at any time point. The concomitant AVR group had more comorbidities, paroxysmal AF, pacemaker implantations (24% vs 5%, p = 0.002), and complications (25% vs 5%, p < 0.001). Freedoms from AF off antiarrhythmic drugs for patients receiving an AVR and pulmonary vein isolation at 1 year was only 50%, which was significantly lower than patients receiving an AVR and Cox-Maze IV (94%, p = 0.001). Conclusions A Cox-Maze IV with concomitant AVR is as effective as a stand-alone Cox-Maze IV in treating AF, even in an older population with more comorbidities. Pulmonary vein isolation was not as effective and is not recommended in this population. A Cox-Maze IV should be considered in all patients undergoing AVR with a history of AF.