A clinical analysis was done on 50 cases of ventricular septal defect, operated from April 1981 to March 1984 at the department of Thoracic and Cardiovascular Surgery, School of Medicine, Keimyung University. Among 50 cases, 34 cases were males and 16 cases were females. Their age ranged from 1 to 26 years and the mean age was 9.7 years. The main symptoms at admission were frequent upper respiratory infection [50%], exertional dyspnea [42%] and palpitation [34%]. In anatomical classification by Kirklin, type I constituted 20%, type II 76%, type IV 4%. Associated congenital cardiac lesions were pulmonic stenosis [6 cases], patent foramen ovale [5 cases], aortic insufficiency [3 cases] and persistent left superior vena cava [1 case]. When a normal electrocardiogram pattern was present, Qp/Qs, Rp/Rs and pulmonary artery systolic pressure and Pp/Ps were relatively low. Among cases of above 1 cm2/M2 BSA in size of defect, Pp/Ps and pulmonary artery systolic pressure were increased than the cases of below 1 cm2/M2 BSA [P=0.01]. The postoperative right bundle branch block was occurred in 21 cases [75%] among 28 cases of right ventriculotomy approach. The operative mortality was 2% [1 case] among 50 cases and complication rate was 14% [7 cases].