Eighteen children with refractory malignant tumors were treated with cis-DDP. They included 10 neuroblastomas, 2 rhabdomyosarcomas, and one each of hepatoblastoma, yolk sac tumor, osteosarcoma and pinealoma. Of 7 cases treated only with cis-DDP, 2 were NC, 6 PD and none were CR or PR. Of 11 cases treated with cis-DDP combined with other agents, 7 were PR, 2 NC, 2 PD and none were CR. The major side effect of cis-DDP was renal toxicity, but this was not serious and only transient. Three cases were treated with the continuous intra-arterial infusion method. These included 2 neuroblastomas and one yolk sac tumor. This treatment was therefore highly effective for children with malignant tumors, and few side effects were observed.