The records of 86 pathologic stage III endometrial carcinoma patients treated at Massachusetts General Hospital between 1974 and 1992 were retrospectively reviewed to identify predictors of poor outcome and to determine the effect of postsurgical therapy on recurrence and survival. Patients underwent TAH/BSO with selective lymphadenectomy and peritoneal washings. Cases prior to 1988 were retrospectively restaged using the FIGO surgical staging criteria. Postoperatively, patients received individualized regimens of EBRT (external beam radiotherapy), brachytherapy, and cytotoxic or hormonal chemotherapy. The 5-year survival and 5-year disease-free survival (DFS) for all patients were 54 and 44%, respectively. Forty-two percent of stage IIIA/B patients recurred in a median time of 14 months. Fifty-four percent of stage IIIC patients recurred in a median time of 16 months. Of patients who recurred, 90% stage IIIA/B and 71% stage IIIC patients recurred at extrapelvic sites. Age greater than 70, high-grade lesions, and fallopian tube metastases were predictive of poor outcome in stage IIIA/B by multivariate analysis. Vascular invasion was the only poor prognostic factor identified by multivariate analysis in stage IIIC disease. No benefit from pelvic EBRT in stage IIIA/B could be identified. Stage IIIC patients had increased DFS and a trend for increased survival with pelvic EBRT. Chemotherapy did not improve survival in either group.