Alagille's syndrome is a common cause of liver disease in children and may lead to the need for orthotopic liver transplantation. Alagille's syndrome is inherited in an autosomal dominant manner, with variable penetration, and may also be present in patients' parents, who may be considered potential donors for living-related transplantation. We report here on two cases in which the living-related donors for children with Alagille's syndrome had no liver function abnormalities or characteristic features of Alagille's syndrome. In both cases, the operation for living-related donation had to be aborted because of a paucity of bile ducts discovered intraoperatively. Given the variable presentation of Alagille's syndrome, we believe that it is necessary preoperatively to evaluate the biliary system of family members who are potential living-related donors for patients with this condition.