This randomized RTOG study evaluated misonidazole radiosensitized radiation therapy in the treatment of malignant glioma. One hundred and forty-six evaluable patients were treated with conventional radiation therapy to 60.00 Gy in 6-7 weeks plus BCNU 80 mg/m2/d for 3 days every 8 weeks (XRT + BCNU). One hundred and forty-seven evaluable patients were treated with misonidazole 2.5 gm/m2 once a week for 6 weeks, radiation therapy to 60 Gy and BCNU (MISO + XRT + BCNU). Patients were stratified according to the prognostic factors of age, performance status, and histology. Distribution of these characteristics was comparable among the treatment groups. The median survival for XRT + BCNU was 55.0 weeks, and for MISO + XRT + BCNU 46.0 weeks (p = 0.35). With patients on a minimum dose of dexamethasone of 3 mg/d, misonidazole neurotoxicity included 8.8% peripheral neuropathy, 2.7% CNS toxicity, and a 0.68% ototoxicity. BCNU pulmonary toxicity occurred in 9.3% of patients who received 902-2062 mg/m2 of BCNU.