Objective: Long-term results after the modified Cox/Maze III procedure combined with other cardiac procedure for the treatment of organic heart disease and chronic atrial fibrillation (AF) has not been clarified. This report describes our medium-term results after such operation. Methods: Between March 1993 and August 1995, 104 consecutive patients with chronic AF underwent the modified Cox/Maze III procedure combined with other cardiac procedure. There were 100 long-term survivors. There were 45 men and 55 women, with ages ranging from 21 to 77 years (mean 59.7). Patients were followed up and changes in rhythm, need for pacemaker implantation, and the incidence of CNS (central nervous system) complications were retrospectively studied. Results: The follow-up was complete in 103 patients and 99 long-term survivors (99%). The mean follow-up period was 44.6+/-1.1 months. In the immediate postoperative period, 73 patients regained sinus rhythm (SR group), 21 patients were in AF (AF group), and six patients underwent pacemaker implantation because of sick sinus syndrome (SSS). During the follow-up period, eight patients died. One- and 5-year survival rates (Kaplan-Meier) after surgery was 95.1+/-2.3 and 87.8+/-3.4% for the entire group. Preoperative NYHA class was 2.5+/-0.7 and medium-term NYHA class was 1.5+/-0.5. (P<0.001) Changes in rhythm for the SR group were followed. Fifty-two patients of the SR group stayed in SR (72%), 16 patients converted back to AF (22%), and four patients had newly-developed SSS (6%) at follow-up period. Probability in SR maintenance for SR group at 1 year was 88.8+/-3.7% and at 5 years was 64.8+/-7.5%. Five patients experienced the CNS complication during the follow-up period. Two of the AF group and two of the SR group patients developed cerebral/cereberal infarction. One of the SR group patients experienced small cerebral bleeding. Conclusions: The medium-term results after the modified Cox/Maze III procedure concomitant with other cardiac procedure are good with improved functional status and good survival rate. However, there seems to be gradual but constant attrition in the rate of SR maintenance in SR group.