The frequency of intraventricular conduction disturbance [IVCD] following right ventriculotomy and right atriotomy approach for ventricular septal defect [VSD] closure was compared in various conditions. Of the 170 isolated VSD patients, 114 patients were repaired via right ventriculotomy and 56 patients were repaired via right atriotomy. The results were as follows; 1. The frequency of IVCD was 45.6% in right ventriculotomy, and 21.2% in right atriotomy group [P<0.01]. The frequency of IVCD following transverse ventriculotomy and vertical ventriculotomy was not significantly different. 2. The frequency of IVCD in subarterial VSD following right ventriculotomy and right atriotomy was not significantly different. But the frequency of IVCD in perimembranous VSD was 50.8% in right ventriculotomy and 27.5% in right atriotomy group [P<0.01]. 3. The frequency of IVCD was higher in groups with larger VSD and it was more significant in right ventriculotomy group. 4. The frequency of IVCD was higher in patch graft closure and it was more significant in right ventriculotomy group. 5. Overall frequency of IVCD was lower in right atriotomy than right ventriculotomy group.