Atrioventricular septal defect with common valvar orifice and tetralogy of Fallot is a rare combination of congenital cardiac anomalies. Approaches to this lesion have tended to emphasize either staged repair or complete repair beyond infancy. Between July 1992 and August 1997, nine patients underwent repair of complete atrioventricular septal defect with tetralogy of Fallot. One patient, aged 9.6 years at the time of repair, had previously undergone construction of a modified Blalock-Taussig shunt. Primary complete repair was performed in the other 8 patients at ages ranging from 2.5 to 16 months (median 4.6 months), and all but one were infants. All patients had a Rastelli type C defect, a single ventricular septal defect with inlet and outlet components, and malalignment of the muscular outlet septum with subpul-monary stenosis. A single patch technique, with closure of the zone of apposition (‘cleft’) in the left atrioventricular valve, was used in all eight patients undergoing primary repair, while a double patch was employed in the previously palliated older patient. In all cases of repair using a single patch, the anterosu-perior bridging leaflet was divided obliquely to the right, following the malaligned outlet septum, in order to avoid subaortic obstruction. Repair of the right ventricular outflow tract included infundibular myectomy in eight, pulmonary valvotomy in four, infundibular or transannular patching in three and one, respectively, and reconstruction with a valved allograft conduit in two patients. There was no early mortality or significant morbidity. At a median follow-up of 45 months, there had been one death related to non-cardiac causes and no reinterventions. Left atrioventricular valvar regurgitation was moderate or mild in two patients, and right atrioventricular valvar regurgitation was mild in one patient. No patient had more than mild pulmonary regurgitation or a gradient across the right ventricular outflow tract in excess of 18 mm Hg. Our results demonstrate that primary repair of atrioventricular septal defect with tetralogy of Fallot can be performed with excellent early and mid-term results in young infants. Although it has been suggested that a technique utilizing oblique division of the anterosuperior bridging leaflet may lead to high rates of atrioventricular valvar regurgitation, medium-term atrioventricular valvar function in the present cohort of patients has been excellent.