Orthotopic liver transplantation remains a major medical and surgical challenge in small pediatric patients. From April 2003 to June 2006, 21 small babies (each of whom weighed less than 10 kg or was younger than 1 year of age) underwent orthotopic liver transplantation. Five were girls and 16 were boys with a mean age of 15.7 +/- 9.3 months (range, 2-24 months); their mean weight at the time of transplantation was 9.8 +/- 3.6 kg (range, 6-16 kg). All transplants were obtained from a living-related donor. Left lateral segment was used for all transplantations. The median graft-to-recipient weight ratio was 3.5% +/- 1.2% (range, 1.5%-6.1%). During the early postoperative period, hepatic arterial thrombosis was identified in 4 patients, and a biliary leak was detected in 2 patients. In 2 patients, portal vein stenosis was identified during the late postoperative period. At the time of this writing, the 17 alive patients (81%) exhibited good graft function at median follow-up of 14.8 +/- 10.9 months (range, 1-39 months). Four patients died during the follow-up. Histological examination revealed hepatocellular carcinoma in 2 patients, and Burkitt's lymphoma in 1 patient. In conclusion, our data confirmed that living-related donors, especially in this age group, provide a reliable source for the organ pool. Satisfactory results can be achieved despite the anatomic handicaps of this age group.