Intensive monochemotherapy with carmustine (BCNU) (either 1,050, 1,200, or 1,350 mg/m2) and cryopreserved autologous marrow transplantation was administered to 36 patients with malignant glioma: 27 with progressive disease and nine without progression (adjuvant therapy group). Twelve (44%) of the patients with progressive disease responded; two remain disease free 84 and 60 months after BCNU treatment. In the adjuvant therapy group, three patients remain progression free at 70, 48, and 27 months after BCNU therapy. Tumor progression posttransplantation occurred in 25 patients; six others died of therapy-induced complications. In addition, late neurologic deterioration of unknown cause has developed in two surviving patients. Results from this and other series using intensive BCNU monochemotherapy and autologous marrow transplantation for progressive malignant glioma indicate that prolonged progression-free survival can be produced in an occasional patient, an extremely unusual result with conventional chemotherapy. Although intensive BCNU and autologous marrow transplant regimens are toxic, these results are encouraging. The treatment of patients in an adjuvant fashion with BCNU and other active agents may produce improved results.