Traditionally, adult bone and soft tissue sarcomas have been considered to be "radioresistant." Because of this philosophy, patients who present with locally advanced, unresectable sarcomas often are treated in a palliative fashion, usually with low-dose radiotherapy. Over the last 6 years, 29 patients with unresectable primary or metastatic sarcomas were treated using a combination of intravenous chemical radiosensitizers and high-dose irradiation. Twenty-two of 29 patients achieved clinical local control, with six patients having a complete clinical response. The time to tumor response is often several months or longer, which is in contrast to other tumor histologies (carcinomas, lymphomas), where tumor response usually occurs over several weeks. Several large tumors have shown only a minimal tumor response, yet were found to be sterilized in posttreatment biopsy or autopsy examination. Of 15 patients with primary sarcomas without metastases, 11 patients (73%) remain free of local tumor progression from 12 to 83 months. Adult high-grade sarcomas can be controlled with high-dose radiotherapy and intravenous radiosensitizers, although the precise role of these agents is unclear.