Three cases of tetralogy of Fallot treated under twelve months of life with aorta-right pulmonary artery anastomosis are reported, in which severe hypoplasia of left pulmonary artery secondary to palliation was present. In the first two cases this complication was not recognized during investigation prior to repair and both died of low cardiac output due to severe right ventricular hypertension. In the third case the complication was evidenced and treated with interposition of a prosthetic valved conduit between right ventricle and confluence of the pulmonary arteries. Hypoplasia or atresia of left pulmonary artery and right pulmonary vascular obstructive disease, secondary to a long-functioning aortopulmonary anastomosis, require surgical consideration identical to tetralogy of Fallot with single pulmonary artery, which is corrected with the use of a valved conduit. The Authors suggest that aortopulmonary shunts should be dismantled within two years and investigation prior to repair should include: 1) exploring of all cardiac chambers and right pulmonary artery through the fistula; 2) injection of contrast medium in right pulmonary artery, aortic root, right ventricle or pulmonary trunk. These diagnostic methods should demonstrate continuity between right ventricle and pulmonary arteries, confluence of pulmonary arteries, and rule out acquired left pulmonary artery atresia, right pulmonary vascular obstructive disease, right ventricular outflow tract atresia.