The impact of para-aortic field radiation therapy upon survival was studied among 26 patients with para-aortic nodal metastases from carcinoma of the endometrium. Seventeen of these 26 patients received postoperative radiation therapy to the para-aortic field as a part of their primary therapy. Sixteen of the 17 also received adjuvant hormonal therapy. Nine of 17 patients (53%) are alive without evidence of disease (18-55 months) with a median survival time of 27 months. Of the remaining eight patients, six (35%) died of endometrial cancer at 6-38 months, with a median survival time of 14.5 months. Five of these patients had distant disease. Two of the 17 patients (12%) died of intestinal obstruction felt to be secondary to radiation enteritis, one of whom was disease free. No difference in survival was detected in patients treated with radiation therapy with microscopic versus macroscopic nodal involvement. Of the nine patients who did not receive para-aortic radiation, eight were treated with hormonal therapy (n = 6) or chemotherapy (n = 2). Seven patients died of disease from 5-28 months, with a median survival time of 13 months. One patient is alive at 12 months. Survival in the 17 patients treated with para-aortic radiation was better than the eight patients not treated with para-aortic radiation (p = 0.004). This survival difference remained significant for patients with microscopic but not macroscopic nodal disease. Para-aortic field radiation appears to improve survival, but has a significant complication rate, and should be reserved for patients with histologic evidence of para-aortic metastases.