The initial experience at the Instituto da Criança do Hospital das Clínicas--School of Medicine of São Paulo University with liver transplantation in children is presented. A staff experienced in the management of children, including pediatric surgeons, hepatologists, critical care specialists, anesthesiologists, and other has been joined to draw therapeutic protocols. Afterward, more than 100 experimental liver transplant were performed in animals of medium size (dogs and pigs). From September, 1989 to July 1991, 12 liver transplants were performed on 9 children (3 retransplants) ranging in age from 2.5 to 17 years, being 5 boys and 4 girls. The donors had been selected according to the ABO blood group and body weight. Just once a blood A+ recipient received a liver from a blood O+ donor. The regular postoperative immunosuppression consisted of triple therapy with cyclosporin, prednisone and azathioprine. The postoperative stay in the Intensive Care Unit ranged from 3 to 24 days, according to the necessity of ventilatory support. These was no intraoperative mortality, arterial or venous thromboses, or early biliary complications. The overall survival is 78% (7/9). Primary non-function of the graft was the cause of death in two of our children. Although the number of cases is still small our results are comparable to those of the best liver transplant centers in the world.