The successful repair of three consecutive cases of tetralogy of Fallot associated with complete atrioventricular canal type C is reported. The correct preoperative diagnosis was established by right and left ventriculography. Operative repair in the first two patients involved division of both hemivalves above the crest of the ventricular septal defect and closure of the septal defects with a single large Dacron patch. In the third patient, the septal defects were closed with two separate patches. The undivided hemivalves were attached to the patches by interrupted sutures placed more to the right side of the midline, so that tricuspid tissue was used to reconstitute the mitral valve. Right ventricular outflow tract obstruction was relieved by infundibulectomy, pulmonary valvulotomy, and placement of a Darcon patch on the infundibulum in Cases 1 and 3. A valved tube was used in Case 2. Six months postoperatively, the condition of the patient is satisfactory. The first patient is receiving digitalis; the second, digitalis and diuretics; and the third patient is well without treatment.