Between 1980 and 1992, 84 patients over 30 years were underwent operative closure of atrial septal defect (ASD). Preoperative complaints and lower cardiac function were more frequent in the older than in the younger, but the clinical symptom of both generation improved significantly after surgery. Only a 67-year-old patient died after surgery due to low cardiac output syndrome. No long-term death occurred. The incidence of atrial fibrillation was increased postoperatively compared with preoperatively. Therefore, we recommend early surgical repair for aged ASD before thirties, if possible.