Infant orthotopic cardiac transplantation has been recently applied to various forms of congenital heart disease with encouraging short-term results. Between June 1986 and September 1987 we evaluated 16 infants for orthotopic cardiac transplantation. Fourteen had hypoplastic left heart syndrome, one had endocardial fibroelastosis with aortic atresia, and one had anomalous pulmonary arterial origin of the left main coronary. Eight families accepted the treatment program and eight families refused (two because of associated anomalies and six on philosophical grounds). Of the eight patients who were candidates for orthotopic cardiac transplantation, one died 6 hours after diagnosis, one was allowed to die after 60 days because of acquired neurologic complications, and another had congenital cytomegalic virus infection. The remaining five patients (four with hypoplastic left heart syndrome, one with anomalous pulmonary arterial origin of the left main coronary) had orthotopic cardiac transplantation. The operation was performed with absorbable polydioxanone suture with deep hypothermia and circulatory arrest in four neonates for hypoplastic left heart syndrome (average time 47 minutes) and bicaval cannulation and continuous bypass in one 11-month-old infant for anomalous origin of the left main coronary. In-house retrieval was used in all. One neonate died of complications as a result of pretransplant donor heart dysfunction and size discrepancy, whereas the remaining three neonates and one infant survived and are home 23 months, 12 months, and 8 months (the patients with hypoplastic left heart syndrome) and 17 months (the patient with anomalous origin of the left main coronary) postoperatively. Triple-drug immunosuppression included cyclosporine, azathioprine, and prednisone. Rejection was diagnosed by clinical evaluation of child activity and monocyte cell cycle analysis from peripheral blood samples without myocardial biopsies. Routine echocardiograms, electrocardiograms, and chest x-ray films were not helpful. Six episodes of rejection were successfully treated in four patients. Twelve-month postoperative catherization in one patient (hypoplastic left heart syndrome) showed appropriate graft growth, no aortic or pulmonary anastomotic strictures, normal right and left ventricular function, and no coronary artery disease. We conclude that infant orthotopic cardiac transplantation is an acceptable procedure for severe forms of untreatable congenital heart disease. The excellent short-term results warrant continued application of orthotopic cardiac transplantation.