Superior vena cava to right pulmonary artery anastomoses have been constructed in 46 infants and children with cyanotic congenital heart disease associated with low pulmonary blood flow and low pulmonary vascular resistance. All children had lesions not currently amenable to corrective operative procedures. Good or excellent results, albeit with persistent mild to moderate cyanosis, followed operation in 31 children and have been maintained for up to eight years. There were 15 hospital and two late deaths. Although there has been a significant absence of late complications, it is probable that the caval anastomosis results in a fixed level of pulmonary blood flow and thus fixed effort tolerance. Thus, when puberty with its demands for increased physical activity occurs, these patients may require further surgery, such as a systemic to pulmonary artery anastomosis to increase pulmonary blood flow.Inadequate pulmonary blood flow in the presence of normal or low pulmonary vascular resistance occurs with a variety of congenital cardiac lesions.Cava-pulmonary circulatory bypass of the right heart, first suggested by Carlon, Mondini, and DeMarchi (1951) and subsequently developed by Glenn and Patifno (1954), Glenn (1958), and Bakulev and Kolesnikov (1959, has become an accepted palliative procedure, mainly of use in patients with tricuspid atresia. Robicsek, Sanger, Taylor, and Najib (1963) Glenn (1958) and consisted of an end-to-side anastomosis of the right pulmonary artery to the superior vena cava followed by ligation of the superior vena cava at its junction with the right atrium. Interrupted 6/0 sutures were used for the anastomosis. Up to 1963, azygos vein ligation at the time of the caval anastomosis was used, but since then in selected patients the technique of delayed azygos ligation (Edwards and Bargeron, 1963)