We report on three children aged 1 1/2, 2 and 9 1/2 years with Wilms' tumor, who developed a tender hepatomegaly and ascites associated with elevated liver enzymes, anemia and thrombocytopenia during chemotherapy. This clinical picture and liver sonography abnormality are best explained by veno-occlusive disease (VOD) of the liver, while other causes of liver disease could not be identified. Actinomycin D dosage was 0.045 mg/kg as bolus injection in two patients and 0.075 mg/kg split over five days in a third patient. Presumable, this drug was the causative agent. VOD was observed after preoperative and postoperative chemotherapy. No child had received abdominal irradiation. The authors comment on the influence of Actinomycin D as the cause for this unusual liver toxicity.