The Fontan procedure has proved useful in the surgical treatment of patients with tricuspid atresia, univentricular heart, and other complicated cardiac anomalies. Previous palliation of these patients with ascending aorta-right pulmonary artery anastomosis (Waterston shunt) may impose severe restrictions in the operability of these patients because of severe distortion, narrowing, and scarring of the proximal right pulmonary artery. A modification of the Fontan operation is described in which repair is facilitated by transecting the right pulmonary artery at the site of anastomosis, trimming away the distorted narrowed segment, and anastomosing the resulting cuff to the lateral aspect of the superior vena cava. The right atrial appendage is anastomosed to the rudimentary right ventricle or the main pulmonary artery directly or via a tubular Dacron graft. The technique has been applied successfully in four consecutive cases.