Four patients aged between 3 1/2 and 16 years were treated surgically for tetralogy of Fallot associated with congenital absence of the left pulmonary artery. This absence, suspected from the chest X-ray, was confirmed preoperatively by angiography of the right and left cavities, aortography, left pulmonary wedged venography and radionuclide scan and substantiated by intraoperative exploration. Congenital absence differs physiopathologically from acquired destruction of a pulmonary branch. In all four patients, repair was performed exclusively on the right branch, without any attempt to introduce a valve in the pulmonary outflow tract and without regard for normal recommendations concerning acquired branch lesions. The only patient to retain a high right ventricular pressure was the one whose pulmonary ring looked sufficiently large to warrant preservation. In all four cases, the postoperative course was uneventful, and the clinical condition is very satisfactory with a follow up of two to twenty-four months. The conclusion would seem to be that the association of tetralogy of Fallot with congenital absence of the left pulmonary artery ascertained with certainty preoperatively, in no way modifies therapy.