Forty-six evaluable pediatric patients with primary recurrent brain tumors resistant to standard therapy were treated with cisplatin, 60 mg/m2/day, X2 days every 3 to 4 weeks, to study the efficacy and toxicity of this drug. Complete and partial responses, documented by computed tomography (CT) scan, were demonstrated in 4 of 10 patients with medulloblastoma and 3 of 15 patients with ependymoma. No activity was documented in astrocytic tumors. Dose limiting major toxicities were renal and auditory. It is recommended that the new analogues of cisplatin with less toxicity be studied in these tumors.