One hundred forty-seven patients with astrocytoma were treated between 1942 and 1967. There were 25 postoperative deaths. The 14 patients in whom the tumor was thought tohave been completely removed were not irradiated and all survived 5 years or longer. Seventy-one of the 108 patients with imcompletely excised lesions received radiation therapy. The 5-year survival rate for those with imcomplete resection alone was 19%, compared to 46% when irradiation was given. Based on observations up to 20 years, after incomplete removal postoperative irradiation significally prolonged useful life and may have lead to permanent control in some. There was no evidence of radiation damage. Most of these tumors were fibrillary astrocytomas, and the results apply particularly to this histologic type. Only 1 of 11 patients with gemistocytic astrocytoma survivied 5 years. The survival rate for Grade i tumors was appreciably greater than for Grade iilesions; in both grades, it was improved by irradiation.