The Southwest Oncology Group conducted a trial of intra-arterial cisplatin (150 mg intravenously every 21 days for 2 doses) administered concomitant with or before radiation therapy. Because of technical difficulties cannulating the artery, 27 of 33 eligible patients were able to receive the cisplatin by arterial injection. Five patients died before completion of the study, and 11 patients in each treatment arm were evaluable for response. Three patients (27%) had an objective tumor regression in each treatment arm. Thromboembolic problems complicated 8 of 57 (14%) chemotherapeutic courses. The median survival for the 33 eligible patients was comparable for both groups: 10.8 months in the concomitant treatment arm and 9.6 months with sequential therapy. Problems related to drug administration and toxicity made it impossible to determine the role of intraarterial cisplatin in the initial management of primary high-grade gliomas.