Complete atrioventricular canal with tetralogy of Fallot is a rare occurrence (8%). Diagnosis rests on the association with Down syndrome and on data from EKG, ultrasonography and angiography. The high operative risk explains why radical surgery is done at an older age (9 years) than in the usual form of complete atrioventricular canal without associated anomalies (33 months) and why antecedent surgical palliation with anastomotic procedures is so frequent (68% of the cases reported in the medical literature). The same surgical procedure was done in all patients: closure of the defects with two separate patches lined with pericardium, suture of the mitral cleft and relief of the infundibular and pulmonary obstruction without valvulation.