Malignant vascular tumors of the liver are rare in children, especially in neonates. We report two cases. One was initially diagnosed as infantile hemangioendothelioma. Rapid growth and appearance of pulmonary metastasis while on aggressive medical treatment suggested malignant transformation. The other neonate presented with intractable ascites and liver biopsy showed histological features of angiosarcoma. Ascites has rarely been reported as a presenting feature of angiosarcoma in literature. Both patients died. To date, surgery, chemotherapy, and radiotherapy have not improved the outcome of malignant vascular tumors of liver.