The study consisted of all patients over 35yerars old undergoing surgical repair of atrial septal defect for the period from June 1985, to August 1992. The following results were observed. 1. ASD was closed with patch in 11 (73%) patients. 2. The relationship of pulmonary artery systolic pressure to Qp/Qs ratio was not significant. 3. Before operation 6 patients were in NYHA functional class II. 8 were in class III, After operation 8 patients were in class I, 6 were in class II. 4. Atrial fibrillation has persisted in 3 patients and returned regular rhythm in 1 patient after surgery. 5. There was no operative mortality and we had good surgical results regardless of patient's age.