Combined treatment with interferon-beta, MCNU (Ranimustine), and radiotherapy was assessed in patients with malignant glioma who had not received previous cytotoxic drug therapy. Forty-three patients up to 75 years old with histopathologically confirmed malignant glioma were studied. All patients had tumors measurable by neuroimaging, a Karnofsky performance score exceeding 40, and an expected survival exceeding 2 months. A response rate of 49% (21/45) was observed, including 6 complete remissions (14%) and 15 partial remissions (35%). Of the 43 patients who completed initial therapy, 19 were given sequential maintenance therapy. Survival time was much longer with than without maintenance therapy. Toxic side effects were moderate and did not substantially affect patients' general condition. We concluded that this combination therapy had a pronounced effect on untreated malignant glioma, particularly in patients whose initial therapy was followed up with maintenance therapy.