Background: Second malignancy is one of the late complications for long-term cancer survivors, treated with radiation or chemotherapy. Various types of second malignancies after radiation therapy for carcinoma of the cervix were reported in the literature. Here, a case of clear cell adenocarcinoma of the uterus, which was misdiagnosed clinically as ovarian tumor, is reported. Case: A 74-year-old multiparous, postmenopausal woman with a past history of radiation treatment for carcinoma of the cervix was admitted as a case of ovarian tumor. At laparotomy, it was recognized as a pyometra with a mass in the cavity of uterus, and the cervix was not seen per vaginum. Results: Subtotal hysterectomy with bilateral salphingo oopherectomy was performed. The histopathology revealed clear cell adenocarcinoma of the endometrium infiltrating the uterus up to the serosa and completely replacing the right ovarian stroma. Conclusions: A second malignancy should be suspected in elderly women who present with a mass in the abdomen or pelvis, and investigations should be directed to rule out the same so that proper management can be planned prior to surgery. ( J GYNECOL SURG 28:379)