Three patients with symptomatic, recurrent supratentorial malignant astrocytoma were retreated with combined interstitial iridium-192 brachytherapy (RT) and hyperthermia (HT): 50 Gy at 50 cGy/h was delivered 10 mm outside the computed tomography (CT) enhancement border through stereotactically placed plastic tubes, and 915-MHz microwave antenna heating was done for 60 min within 30 min either before or after irradiation. Invasive thermometry data were obtained from the tumor and adjacent brain tissue. The patients tolerated the treatment well and two thirds improved. All patients developed cerebral edema, one also developed scalp infection, and another patient developed meningeal infection. Exceeding the expectancy without treatment, overall survival was 7, 12, and 15 months. On autopsy, two of the patients' brains revealed no active tumor in the treated regions, but one displayed tumor in untreated parts. The HT-RT treatment was very effective, but the original tumor extent was not apparent by the CT imaging technique. A postimplant resection approach may be advisable to minimize postimplant edema. Our data are in agreement with the available literature on more than 400 patients. However, our aim of extending survival decisively could not be realized.