Hepatoblastoma, the most common and peculiar tumor of the liver in infancy and childhood, has recently been the object of an international protocol of the European (SIOP) Histopathological Study Group in order to establish common anatomicoclinical criteria provided with therapeutic and prognostic significance. A general review of hepatoblastoma concerning its possible association with congenital anomalies, endocrine and metabolic disorders, as well as physical and laboratory data, macroscopic and histological patterns, is reported. The different histotypes of hepatoblastoma, represented by anaplastic, embryonal, fetal, mixed (epithelial and mesenchymal) and teratoid, are described, and hypothesis of the pathogenesis of this tumor is discussed, based upon immunohistochemical investigations.