In a phase II trial, cisplatin was given by two randomly assigned dose schedules to 53 children with malignant solid tumors. Both schedules, 30 mg/m2/week and 90 mg/m2 every 3 weeks, were associated with drug-related toxic effects involving the renal, hematopoietic, and neuromuscular systems. Pharmacokinetic studies indicated that the initial serum half-life of total platinum was 27.6 minutes, with a terminal half-life of 44.4 hours. Significant antitumor effect was noted in patients with neuroblastoma and malignant germ cell tumors. Use of cisplatin in combination therapy for patients with these diseases is indicated.