Fifty-two patients with tetralogy of Fallot underwent repair between March 1985 and July 1987. The repair was made without a ventriculotomy whenever feasible. There were no (0%) early or late-phase deaths (70% confidence limits 0% to 3.6%). Operative reports and preoperative angiocardiograms were retrospectively reviewed to delineate determinants for operative approach. Two distinct morphologic subgroups were observed angiographically and confirmed intraoperatively. Thirty-two patients (62%) had severe hypertrophy of the infundibular septal structures. Each of these 32 underwent transatrial and transpulmonary repair of the infundibular stenosis, and 12 of them also required a limited ventriculotomy to enlarge a hypoplastic pulmonary valve anulus. The other 20 patients (38%) were found to have hypoplasia and not hypertrophy of the infundibular septum. Each of these required a formal transventricular approach to the repair with an infundibular patch inserted to relieve the infundibular stenosis. Right ventricular/left ventricular systolic pressure ratios after repair were not different between the groups (p = 0.79). In conclusion, tetralogy of Fallot was satisfactorily repaired by means of a transatrial and transpulmonary approach in two thirds of these patients. The avoidance of a ventriculotomy to accomplish repair may be suggested preoperatively by selective angiocardiogram and confirmed by intraoperative assessment. These findings have important implications for the development of treatment protocols.