Liver tumors in children are rare, potentially complex, and encompass a broad spectrum of disease processes. Any age group may be affected, including the fetus. Most present with abdominal distension and/or a mass. Accurate preoperative diagnosis is usually possible using a combination of ultrasound scanning and cross-sectional imaging techniques (CT and/or MR), supplemented by liver biopsy and measurement of tumor markers. The most common benign tumors are hemangiomas, but mesenchymal hamartoma, focal nodular hyperplasia, and adenoma also are found. In Western countries, hepatoblastoma is the most common primary malignant liver tumor; disease-free survival is now possible in more than 80% of affected patients because of advances in combination chemotherapy, improved techniques of surgical resection, and the selective use of liver transplantation. In contrast, there has been less progress in the management of hepatocellular cancer, which still poses many therapeutic challenges.