Forty-one infants and children with primary tumors of the liver have been evaluated as to cell type, age, sex, symptoms, diagnosis, therapy, and results. Twenty-six (60%) harbored malignant hepatomas, and there was one case each of malignant teratoma and mesenchymoma. Thirteen lesions were histologically benign. Twenty-seven (66%) of the patients were less than 2 years of age, half were males, and most were admitted with an asymptomatic abdominal mass. Tumor localization was accomplished by conventional roentgenographic and scanning techniques. Three patients were diagnosed at autopsy and 38 underwent exploratory operation. Twenty-two tumor resections were completed with three operative deaths. All patients with benign tumors and three of the nine (33⅓3%) of the hepatoma patients have remained well five or more years. Additional success may be accomplished by combining radiation, chemotherapy, and second-look resections.