A 4-month-old infant with repeated painful shock-like episodes was shown by the progression of electrocardiographic findings to have coronary insufficiency and finally a myocardial infarction. Selective cineangio-cardiography demonstrated anomalous origin of the left coronary artery from the main pulmonary artery with flow from the pulmonary artery to the myocardium. Preparations for surgical transplantation to the aorta were being made when the infant died. The feasibility of the proposed operation was demonstrated post mortem. A segment of the main pulmonary artery was excised with the coronary ostium at its base and converted into a tube which was anastomosed to the aorta. The defect in the pulmonary artery was repaired with a patch graft of Dacron.