A retrospective survey of 41 patients with unbiopsied thalamic, pontine, and medullary tumors treated with radiation therapy demonstrated 30% to 40% 3-year survival, with seven long-term survivors. Eleven of the 12 patients surviving over 3 years have essentially normal neurological function. Of seven patients in whom histological diagnoses were eventually obtained, four proved to have glioblastomas and three low-grade astrocytomas. Autopsy revealed that all glioblastomatous tumors extended beyond the treatment field; this suggested that larger volumes, perhaps the whole brain, should be irradiated. High doses (at least 5000 rads) should be used since the 3-year survival among those receiving such doses was 45%.