Eighty-one patients with recurrent primary or metastatic brain tumors were treated with carmustine (BCNU [1,3-Bis(2-chloroethyl)-1nitrosourea]) alone or carmustine and vincristine sulfate combined, and their responses analyzed. A response was defined as a clear clinical improvement unrelated to corticosteroid therapy. The overall response rate with carmustine was 48% and with the combination, 30%. In patients with glioblastoma, the response rates were 53% and 25%, respectively. The most responsive tumors were ependymomas; the least responsive, metastatic. The dose-limiting toxicity of carmustine was exclusively hematologic; of vincristine, exclusively neurologic, and severe enough to make drug effectiveness difficult to assess. We conclude that carmustine is an effective chemotherapeutic agent, with an acceptable level of toxicity, for the treatment of brain tumors. Vincristine did not enhance the effectiveness of carmustine and we have discontinued the use of these drugs in combination.