A clinical analysis of 138 cases of ventricular septal defect operated on from 1983 to June 1988 at the department of Thoracic and Cardiovascular Surgery, School of Medicine, Chung-nam National University was done. The following results were obtained. 1. The VSD were 27.6 % and 41.0 % respectively of 500 open heart surgery cases and 334 congenital heart disease. 2. The range of age when the VSD was repaired was 3 months to 45 years, the mean age was 10.4 years and the 53.6 % of patients were under 7 years. The sex ratio was 6:4 in males favor. 3. The two common symptoms were frequent upper respiratory infection and dyspnea whose frequency was 62.5 % and 58.7% respectively. 4. 52% of the patients was below 25 percentile of the standard body weight. 5. The most common chest PA findings were cardiomegaly and increased pulmonary vascularity. 6. On anatomical classification, perimembranous type was most common [65.5%], subpulmonary arterial type was 27.6 %, perimembranous plus subpulmonary arterial type was 3.4 % multiple VSD was 0.8 % and LV-RA defect was 2.6 %. 7. Associated cardiac anomalies were founded in 39 cases [35.5 %] and PDA and aortic valve prolapse were most common associated anomalies and extracardiac anomalies were founded in 6.7 % of patients. 8. Mean extracorporeal circulation time was 68 min. and mean aortic cross-clamping time was 42 min. 9. The postoperative complications developed in 26 % of patients and the most common one was minor wound infection. 10. Right bundle branch block developed in 54.8% of the patients who had right ventriculotomy, 40.0% of the patients who had right atriotomy and 10.5% of the patients who had pulmonary arteriotomy. 11. The overall operative mortality was 5.1 % and the operative mortality of the patients who body weigh under 10 Kg was 23.8%.