Seventeen patients with recurrent gliomas were treated with the combination of cyclophosphamide and vincristine. All but one had previously received and failed chemotherapy. Cyclophosphamide was administered at doses ranging from 250 to 1000 mg/sq m by intravenous infusion on Days 1 and 2, and vincristine was given at a dose of 1.0 mg/sq m (2 mg maximal dose) intravenously on Day 1; cycles were repeated every 4 weeks. Clinical and radiographic improvement was observed in eight of 16 evaluable patients, and four other patients had stabilization of previously progressive disease. Four patients are alive and off treatment without evidence of recurrence for a median period of 37 months; these included an adult with a cerebral anaplastic astrocytoma now more than 51 months after therapy. Toxicity included moderately severe myelosuppression that required hospitalization in seven patients. These results indicate that the combination of cyclophosphamide and vincristine has activity in the treatment of recurrent gliomas, and warrant the use of these drugs in larger controlled studies, particularly if they can be used in conjunction with hematopoietic growth factors.