Background: The efficacy of Cox-maze III procedure was reported in eliminating AF in patients with preoperative chronic AF undergoing valvular surgery. Since adding the maze procedure to valvular surgery complicates the operation, there is a concern that the combination will result in increased early mortality and morbidity. The objective of this study is to evaluate the risks and benefits of adding the maze procedure to valvular surgery.Methods: Between October 2002 and December 2004, 20 patients with chronic AF underwent the maze procedure combined with valvular surgery (maze-group). They were compared to 20 patients with chronic AF underwent valvular surgery without maze procedure (non-maze group). Both groups were matched for age, sex, duration of AF, number of antiarrhythmic drugs. Postoperatively and during late follow-up all patients were followed by 12-lead ECG and echocardiography.Results: There was no mortality in both groups. The duration of cardiopulmonary bypass (P=0.0001) and aortic cross clamp (P = 0.0001) were significantly longer in the maze group. No significant statistical difference was found between both groups as regard the incidence of postoperative complications, amount of bleeding and duration of ICU and hospital stay. At the latest follow-up 90% of the maze patients were in sinus rhythm compared to 15% in non-maze patients (P = 0.0001).Conclusion: The maze procedure didn't seem to increase the operative mortality and morbidity when added to valvular surgery, was effective in eliminating AF and reduced the risk of thromboembolic complications.