The authors discuss the results of clinical trials assessing the value of chemotherapy for brain tumors in the adjuvant setting as well as at recurrence. Adjuvant chemotherapy does benefit some patients with malignant brain gliomas. Improved survival rates seem to be related to an increased number of long-term survivors. The most effective chemotherapy is BCNU or a combination of CCNU, procarbazine, and vincristine (PCV). Drugs that potentiate radiation therapy, such as hydroxyurea and BUdR, are also useful in some patients.