Over the past decade we have reported excellent outcomes in pediatric living-donor liver transplantation (LDLT) with recipient survival exceeding 90%. Principles established in these patients were extended to LDLT in adults. To compare outcomes in donors and recipients between adult and pediatric LDLT in a single center, we reviewed patient records of 45 LDLT performed between 1/98 and 2/01: 23 adult LDLT (54 +/- 6.5 yr) and 22 pediatric LDLT (33.7 +/- 53.5 months). Preoperative liver function was worse in adults (International Normalized Ratio [INR] 1.5 +/- 0.4 vs. INR 1.2 +/- 0.5; p = 0.032). 4 adults (17%) met criteria for status 1 or 2A. Only 1 child was transplanted urgently. Analysis included descriptive statistics and Kaplan-Meier estimation. Donor mortality was 0% with 1 re-exploration, 2.4%. Median hospital stay (LOS) was 6.0 days (range, 4-12 days). Donor morbidity and LOS did not differ by sex, extent of hepatectomy, or adult and pediatric LDLT ( p = 0.49). In contrast, recipient outcomes were worse for adults. Adult 1 year graft survival was 65% (3 retransplants [ReTx], 5 deaths) vs. 91% for children (1 ReTx, 1 death) p = 0.02. Graft losses in adults were due to sepsis (n = 3), small for size (n = 2), suicide, and hepatic artery thrombosis (HAT), whereas in children graft losses were due to portal thrombosis and total parenteral nutrition (TPN) liver failure. Biliary leaks occurred in 22% of adults and 9% of children. Hepatic vein obstruction occurred in 17% of adults and in none of the children. Median LOS was comparable (adult, 16.5 days (range, 7-149 days); child, 17 days (range, 10-56 days), p = 0.2). Graft function (total bilirubin (TBili) < 5mg/dl, INR < 1.2, aspartate aminotransferase (AST) < 100 U/l) normalizing by day 4 in children and by day 14 in adults. Adults fared worse, with an array of problems not seen in children, in particular, hepatic vein obstruction and small-for-size syndrome. Biliary leaks were diagnosed later in adults and were lethal in 3 cases; this was later avoided with biliary drainage in adult recipients. Finally, use of LDLT in decompensated adults led to death in 3 of 4 patients, and should be restricted to elective use.