To date, 92 heart transplants have been performed as part of the pediatric heart transplant program started at the Necker Enfants Malades/Laennec Hospital in Paris in 1987. One-third of patients were younger than two years of age at transplantation, and nine were younger than nine months. The most common reason for transplantation was cardiomyopathy (64%), which was usually of the dilated hypokinetic type; 33 patients (36%) had congenital heart defects. Maintenance immunosuppressant therapy usually consisted of cyclosporin and azathioprine, with in some cases Low-dose corticosteroid therapy. The postoperative complication rate was high. The most common early complication was acute rejection, whose diagnosis relied primarily on endomyocardial biopsy. Infections were.-very common during the first six months; after a phase of dominant bacterial infections, viral infections became more common. Cyclosporin caused renal dysfunction in some cases. Immunosuppressant-induced lymphoproliferative disorders occurred in eight patients and were severe in five. The main long-term complication was coronary artery disease, which was responsible for complete coronary artery occlusion in some cases. Mortality rates were about 22% during the first month and 26% subsequently. Most late deaths were due to coronary artery disease, rejection, or lymphoproliferative syndrome. Most survivors enjoyed an excellent quality of life and were able to engage in normal physical activities.