Although tremendous improvement in the treatment of childhood cancer has resulted from the use of clinical trials, it is clear that additional significant progress will require a better understanding of the molecular makeup of pediatric malignancies. Hepatoblastoma, an embryonal tumor of the liver, is rare in the general population. It occurs in approximately 1 in 50,000 children. However, families affected with Familial Adenomatous Polyposis, in which there is a high incidence of colon cancer, have an 850 fold increase in the frequency of Hepatoblastoma. Hepatoblastoma also occurs in association with Beckwith-Wiedemann Syndrome. Thus the occurrence of Hepatoblastoma suggests the need for both careful investigations into the family history of malignancies in relatives, as well as a search for genetic alterations that may contribute to tumor development.