The case histories of 40 patients with gliomas of the thalamus and midbrain (group I) or caudal brain stem (group II) were reviewed to determine the effect of radiation therapy on neurologic functional status and survival. Nine of 14 (64%) patients in group I demonstrated an improvement in functional status following radiotherapy, as did 19 of 26 (73%) patients in group II. Eight (57%) patients in group I and 10 (38%) patients in groups II are alive with no evidence of disease after periods of 12-65 mo. following completion of treatment. Actuarial survival data indicate a better survival rate in group I patients. Based on the present findings, an aggressive and potentially curative attempt with use of radiation therapy for gliomas of the thalamus, midbrain and brain stem is justified.