Twenty five patients with tumors of the brain stem were treated with radiotherapy between 1979 and 1987. Histological diagnosis could be obtained in 6 cases, and other 19 patients were diagnosed by neurologic findings and CT or MRI. Eighteen patients were treated by radical radiotherapy and 6 patients received both operation and radiotherapy, while 1 patient received chemotherapy after radiotherapy. Total dose ranged from 50 Gy to 55 Gy. By an clinical scoring scale at 2 months after radiotherapy, no complete response was obtained, but 16 cases achieved partial response, 2 cases were stable, and 4 cases were deteriorated. The overall survival rate at 3 years was 36%. Age, performance status at diagnosis, degree of cranial nerve involvement, CT pattern of post-contrast enhancement, and clinical response by scoring scale were correlated with survival.