The carcinogenic effect of ionising radiation in humans has well documented in both atomic bomb survivors and patients exposed to therapeutic radiation. Patients irradiated for cancer of cervix have frequently been studied for the later development of secondary malignancies because treatment is relatively successful and many patients survive long enough to be at risk for late complications of radiotherapy. Most investigations have revealed an increased incidence of uterine sarcoma following pelvic radiation therapy for a variety of gynecologic disorders (Norris and Taylor, 1965; Fehr and Prem, 1974). Wagoner, in a review of over 1800 women treated with ionising radiation for invasive cervical cancer, reported a fourfold increase in risk for the later development of uterine sarcoma (Wagoner, 1984). In this paper we report the case of uterine papillary serous carcinoma 16 years after pelvic X-ray therapy for cervical cancer.