cis-Dichlorodiammineplatinum(II) (cis-platinum) was evaluated in three separate studies at Roswell Park Memorial Institute in children and adolescents with cancer. In the first study, 16 patients with a variety of solid tumors were treated. Objective responses were seen in patients with neuroblastoma, osteogenic sarcoma, seminoma, and medullary carcinoma of the thyroid. In the second study, five of eight patients with far-advanced osteogenic sarcoma showed objective responses to cis-platinum. In the third study, cis-platinum and Adriamycin were employed as primary adjuvant chemotherapy along with surgery in osteogenic sarcoma. Nine of ten patients have remained disease-free from 8 to 31 months (mean, 19 months). cis-Platinum is an active agent in pediatric tumors.