Thirty patients with recurrent malignant glioma were treated with intravenous (IV) carboplatin (CBDCA) every 4 weeks at a starting dose of 400 mg/m2 escalating to 450 mg/m2. All patients had documented recurrent tumor after prior radiotherapy but had not received prior chemotherapy. Of 29 assessable patients, four (14%) responded to the treatment for 44, 51+, 72, and 91 weeks; 10 (34%) achieved stable disease (S); while 15 (52%) had progressive disease (P). The total response (responses plus S) rate was 48%, with a median time to progression (MTP) of 26 weeks in these patients; the MTP for all 29 patients was 11 weeks. The toxic effects were mainly hematologic, with thrombocytopenia and granulocytopenia being mild at 400 mg/m2 and 450 mg/m2 doses. NO neurotoxicity or renal toxicity was encountered. These results suggest that CBCDA given at 400 mg/m2 or 450 mg/m2 every 4 weeks is marginally active in patients with recurrent malignant gliomas. Since hematologic toxicity is mild, a higher dose could possibly be given, and may increase the response rate.