A child with the Alagille syndrome of intrahepatic bile duct paucity developed hepatocarcinoma. Disabling cirrhosis had rendered this child a suitable candidate for transplantation before the discovery of carcinoma. However, the extension of the tumor outside the liver precluded the performance of this potentially life-saving operation. Serial monitoring of the serum alpha-fetoprotein concentration may be of value in the early identification of tumors in pediatric candidates for transplantation.