Thirty-six patients were evaluated between 1965 and 1983 for glioma of the optic nerves and/or chiasm. Median follow-up was 10.2 years. Pathologic verification was obtained in 32 patients. Tumor initially confined to the optic nerve recurred in one of five patients after complete resection. The actuarial survival for 25 patients irradiated for biopsy-proven glioma of the optic chiasm was 96%, 90%, and 90% at 5, 10, and 15 years, respectively, and the progression-free survival was 87% at 5, 10, and 15 years. Vision stabilized or improved in 86% of patients after radiotherapy. Patients irradiated to a dose greater than a NSD of 1385 ret had a significantly improved progression-free survival (P = 0.015). One serious complication occurred after a dose of 1533 ret. The recommended radiation dose for optic glioma is 45 to 50 Gy with 1.8 Gy fractions.