Carboplatin was administered at 1,000 mg/m2/course in combination with etoposide at 300 mg/m2/course to 23 patients aged 5 months to 16 years. Five patients were affected by neuroblastoma, four by CNS tumors, three by Ewing's sarcoma, two by rhabdomyosarcoma, two by malignant teratoma, two by Wilms' tumor, two by head and neck carcinoma, one by hepatoblastoma, one by synovial sarcoma, and one by Langerhans-cell histiocytosis. Eleven patients were pretreated, seven of them with high-dose cisplatin. The overall response rate was 7/11 (64%) for pretreated and 10/12 (83%) for previously untreated patients. Myelosuppression was the main side effect, with anemia and thrombocytopenia more pronounced than leukopenia. Gastrointestinal toxicity and ototoxicity were very mild; nephrotoxicity and neurotoxicity other than hearing loss were not observed. In children with malignant tumors, the therapeutic activity of carboplatin at high doses, even in combination chemotherapy, deserves further studies.