Although liver transplantation is now accepted as the ideal therapy for end-stage liver disease, relatively few centers have gained a large experience in children, and good results have been elusive. Technical difficulty and a high incidence of graft failure are among the obstacles to success. At the University of California at Los Angeles, 39% of our liver transplants are in the patients who are younger than 18 years. We have analyzed our experience with 103 patients to emphasize factors important to a favorable outcome with the procedure. One hundred twenty-three transplants were performed in 103 children (mean age, 5.2 years; 48% younger than 3 years). No reduced-size grafts were used. Scrupulous attention to technical details of the vascular reconstruction, including frequent use of the supraceliac aorta of the recipient and interrupted suture techniques, ensured construction of sound hepatic artery and portal vein anastomoses at the first operation. Preoperative exchange transfusions were used if the prothrombin time was prolonged beyond 7 seconds, resulting in an average blood loss of only 3.3 volumes. Cyclosporine dosage was maintained in the high therapeutic range for the first 4 weeks, and anti-T-cell antibody (OKT3) was used for rejection (38%). Amphotericin prophylaxis was used for biliary atresia patients with multiple previous operations. Eighty-two of one hundred three patients (80%) are alive. There were no intraoperative deaths. Actuarial survival rates at 6 months, 1 year, and 5 years are 80%, 79%, and 77%, respectively. Survival of patients who underwent transplantation at age less than 1 year is 65% versus 85% at age more than 1 year (p = 0.08). Retransplantation was performed in 19 patients (18%), with a survival rate of 58%. Hepatic artery thrombosis, the most frequent technical complication, occurred in only 16 patients (13%). Survival rates of ABO identical-match versus nonidentical-match grafts were 96% and 60%, respectively (p = 0.02). Graft survival was only 47% if more than one steroid cycle was needed, compared to 75% survival with OKT3 treatment. Despite impairment of renal function (glomerular filtration rate [GFR] less than 80 cc/kg/min) in 54% of patients and hypertension requiring therapy in 27%, 90% of the children demonstrated enhancement of growth, development, and functional status. The following conclusions were made. (1) Pediatric liver transplantation is the treatment of choice for all types of end-stage liver disease and should be considered early. (2) Factors that enhance survival include technical precision, aggressive retransplantation, antifungal chemoprophylaxis and therapy, and judicious immunosuppression with use of OKT3 for rejection.(ABSTRACT TRUNCATED AT 400 WORDS)