Defects of the ventricular septum are the commonest tpe of congenital cardiac malformations. A classification with axial angiography of the subtypes of ventricular septal defects is proposed on the study of 126 patiendts with defects of the ventricular septum. The results were as follows; 1. The incidence of the ventricular septal defect was 39.6% of congenital heart malformation. 2. The sex distribution of cases were 70 males and 56 females the age ranged from 13 months to 26 years. 3. Angiographic features seen by axial angioraphy were as follos; a. perimembranous defects as seen on long axial view of left ventriculogram were in continuity wity aortic valve. The relation of the defect to the tricuspid valve allows distinction of the extension of the perimembranous defect toward inlet trabecular or infundibular zones. This relation was determined angiographically using the courese of the contrast medium from the left ventricle through the ventricular septal defect opacify-ing the right ventricle. In inlet excavation the shunted blood opacified the recesas between septal leaflet of tricuspid valve and interventricular septum in early phase in infundibular excavation opacified the recess between anterior leaflet of tricuspid valve and anterior free wall of right ventricle and intrabecular excavation the shunted blood and anterior free wall of right ventricle and in trabecular excavation the shunted blood traversed anterior portion of tricuspid valve ring opacified trabecular portion of right ventricle b. Musculardefects were separated from the semilunar and atrioventricular valves. c. Subarterial defects were related to both semilunar valves and they were best demons-trated on the elongated right anterior oblique view of the left ventriculogram. d. Total infundibular defects were profilled in right anterior obique 30 and long axial view subaortic in location in both views. 4. The incidence of subtypes of ventiricular septal defects evaluated by axial angiography were as follows; Subarterial type 18 cases(14.3%) Total infundibular defect 1 cases(0.8%) Perimembranous type 100 cases(79.4%) Infundibular excavation 60 cases(47.6%) Trabecular excavation 10 cases(7.9%) Inlet excavation 30 cases(23.8%) Muscular defect 7 cases(5.6%) Infundibular excavation 6 cases (4.8%) Trabecular excavation 1 cases (0.8%)