From 1977 through 1984, 97 patients of V.S.D. were treated surgically at Department of Thoracic and Cardiovascular Surgery, Korea University college of Medicine. Among 97 patients, 3 patients were treated by PDA ligation, 3 patients were treated by PDA ligation and subclavian flap aortoplasty, 1 patient were treated by pulmonary artery banding. All of the above patients were analyzed clinically. The results were as follows; 1. Of the patients, 52 patients were male [55.5%] and 45 patients were female [44.5%]. Their age ranged from 7 days to 32 year, and the mean age was 9 year of age and 28.9% of patients were between 4 and 8 year of age. 2. The most common clinical symptoms were frequent U.R.l. and D.O.E.. 3. The most common chest PA findings were cardiomegaly and increased pulmonary vascularity. 4. Associated anomaly was founded in 27 cases and PDA was most common associated anomaly and others were A.S.D., pulmonary stenosis, aortic regurgitation, D.C.R.V.. 5. Pulmonary hypertension was founded in 37 patients and it`s incidence was increased by patient age and shunt amount. 6. On Kirklin`s anatomical classification, type 11 defect was most common [45.5%], and type 1 was 35.5%, and type 111 was 4.4%, and type 1V was 4.4%. 7. Mean E.C.C. time was 69.1 min. and varied by closing method and associated anomaly as in case of simple closure; 47.8 min., in case of patch closure; 77.2 min., in cases with associated anomaly; 92.7 min.. 8. Mean postoperative ventilatory assisted time was 7.3 hour and varied by preoperative pulmonary artery pressure and E.C.C. time, as the group with pulmonary hypertension; 10.5 hour, the group without pulmonary hypertension; 5.5 hour, the group of short E.C.C time [within 1 hour]; 4.4 hour, the group of long E.C.C. time [over 1 hour]; 8.4 hour. 9. Overall operative mortality was 9.3% [9 cases].