Despite numerous studies documenting reduction of pelvic relapses after adjuvant pelvic radiotherapy stage I and II uterine sarcomas, improved survival remains unproven. This retrospective report analyzes patterns of failure, survival, and toxicity in 42 women with stage I and 7 patients with stage II uterine sarcomas treated from 1972 through 1998 to identify patients likely to benefit from pelvic or abdominal radiotherapy and chemotherapy. Four of these patients also received adjuvant chemotherapy. There were 20 leiomyosarcomas, 18 homologous mixed mullerian tumors, and 11 heterologous mixed mullerian tumors. Disease-free survivals for mixed mullerian tumors were 65% at 5 years and 61% at 15 years. Disease-free survivals for leiomyosarcomas were 40% at 5 years and 40% at 15 years. There were 14 distant only, 5 distant and abdominal, 1 abdominal, 1 distant and pelvic, and 2 unknown initial sites of failure. Acute toxicity was acceptable as measured by a median 1-kg weight loss from radiotherapy and a 2% rate of failure to complete therapy. Chronic toxicity consisted of 3 small bowel obstructions and 1 sigmoid colon obstruction. In conclusion, the efficacy of adjuvant pelvic radiation is demonstrated by the absence of any isolated pelvic failures. Although the frequent occurrence of peritoneal failures suggests a role for prophylactic abdominal radiation for mixed mullerian tumors, more effective systemic therapy is necessary to substantially increase the chance of cure for women with early-stage uterine sarcomas.