Twenty-seven patients aged 1 to 18 years harboring supratentorial (20 in the cerebrum and seven in the thalamus) malignant gliomas were treated between 1975 and 1982. There were four glioblastomas multiforme, 14 anaplastic astrocytomas, and nine malignant gliomas. All patients had a subtotal resection or biopsy as the initial procedure and received postoperative radiation therapy (RT). Fifteen of 27 patients were treated by RT alone; 14 had tumor progression with a median time to tumor progression (MTP) of 65 weeks. Twelve patients were treated with chemotherapy as an adjuvant to RT; only seven had tumor recurrence, with an MTP of 130 weeks. Of the 21 patients with recurrent tumors in both groups, 18 were treated with chemotherapy alone, or chemotherapy with a second surgical procedure or second course of RT. For all histological grades of tumor, the MTP for first recurrence was 75 weeks and the median survival time was 180 weeks. Age at initial diagnosis was found to be a statistically significant prognostic factor, with patients younger than 10 years of age surviving longer than patients aged over 10 years (p = 0.02).