Since December 1979, 14 patients with progressive metastatic brain lesions have been treated with temporary implantation of high-activity iodine 125 sources using stereotaxic techniques. Four patients had prior surgical resections, and 13 had been treated with external whole-brain radiotherapy. Nine patients had brachytherapy performed at recurrence 4 to 16 months after conventional radiation therapy; the other four had implants as an adjuvant "boost" to the tumor area from 2 to 4 weeks after external radiation. Six patients have since died: two with stable brain lesions at 4 and 22 weeks, respectively; three with progressive systemic and CNS tumors at 23, 24, and 29 weeks, respectively; and one with progressive CNS disease 116 weeks postimplant. The remaining eight patients are alive with a median follow-up of 63 weeks (range, 52-239+ weeks). Median survival for the entire group is 80 weeks. Brain tumor brachytherapy may be useful for palliation and possible long-term survival in selected patients with solitary metastatic disease.