Surgery is the accepted form of treatment of meningioma; the role of radiotherapy has not been clearly established. With this in mind, we have reviewed our experience with radiation therapy in the management of meningiomas at New York University Medical Center. Sixty-eight patients fell into three groups. Forty-three (Group A) underwent operation followed by radiation therapy, 14 patients (Group B) had radiation for recurrence after operation, and 11 patients (Group C) had radiation therapy as the primary treatment. In Group A, 41 of 43 are alive. During a follow-up of 1 to 10 years, only 2 have deteriorated. Five of 14 Group B patients showed neurological improvement and 7 showed deterioration, including 5 who died of tumor. All 11 patients in Group C are alive with follow-up periods of 3 to 6 years; 9 of these show improvement in neurological function. Eleven patients had malignant meningioma, of whom 8 are alive and stable. We present 4 case reports, including computed tomographic scans that show evidence of tumor necrosis after radiation therapy. Pathological verification of tumor necrosis is presented in 1 case. We believe that radiation therapy has an established role in the treatment of incompletely excised, recurrent, or malignant meningiomas and, in some cases, as the initial management of meningiomas. Indications for treatment and guidelines are presented.