Abstract In a clinical trial, 10 patients with malignant gliomas underwent partial resection of their tumors and were treated by intraarterial 1,3-bis(2-chloroethyl)-l-nitroso-urea (BCNU) chemotherapy. The drug was given at least 1 month after the completion of postoperative radiotherapy in total doses of 270–280 mg/m 2 in two sessions separated by a 48-hour interval (the two sessions with interval were equal to one course). This therapy was repeated every 8–10 weeks. Four patients had three courses and the other six patients had two courses of chemotherapy. This therapy was the only antitumor chemotherapy for this group of patients. Our preliminary results demonstrate the safety of this new procedure and suggest that intraarterial BCNU chemotherapy may be more effective, and has a better tolerance and less toxicity, than intravenous BCNU chemotherapy. Furthermore, it was demonstrated that, in the case of one patient, higher antitumor activity resulted from intraarterial BCNU chemotherapy as compared to intravenous BCNU therapy.