Patients with high-risk endometrial carcinoma (stage IcG3, IIG3 with myometrial invasion >50%, and III) receive adjuvant therapy after surgery but it is not clear whether radiotherapy (RT) or chemotherapy (CT) is better. We randomly assigned 345 patients with high-risk endometrial carcinoma to adjuvant CT (cisplatin (50 mg m(-2)), doxorubicin (45 mg m(-2)), cyclophosphamide (600 mg m(-2)) every 28 days for five cycles, or external RT (45-50 Gy on a 5 days week(-1) schedule). The primary end points were overall and progression-free survival. After a median follow-up of 95.5 months women in the CT group as compared with the RT group, had a no significant hazard ratio (HR) for death of 0.95 (95% confidence interval (CI), 0.66-1.36; P = 0.77) and a nonsignificant HR for event of 0.88 (95% CI, 0.63-1.23; P = 0.45). The 3, 5 and 7-year overall survivals were 78, 69 and 62% in the RT group and 76, 66 and 62% in the CT group. The 3, 5 and 7-year progression-free survivals were, respectively, 69, 63 and 56 and 68, 63 and 60%. Radiotherapy delayed local relapses and CT delayed metastases but these trends did not achieve statistical significance. Overall, both treatments were well tolerated. This trial failed to show any improvement in survival of patients treated with CT or the standard adjuvant radiation therapy. Randomised trials of pelvic RT combined with adjuvant cytotoxic therapy compared with RT alone are eagerly awaited.