Gestational trophoblastic neoplasia (GTN) is a disease with a course of trophoblastic proliferation, and histologically classified as partial hydatidiform mole, complete mole, invasive and metastatic mole, choriocarcinoma and placental site trophoblastic tumor. Occurrence of GTN in postmenopausal women is rare.We report the case of a 56-year-old postmenopausal woman with a complete mole. The patient was admitted to gynecology outpatient clinic with abdominal pain, nausea and vomiting for about 1 month. Ultrasound examination revealed enlargement of the uterus with endometrial thickness containing hypo/hyper echogeneous and cystic areas. Serum beta-HCG was tested against the possibility of GTN because of the appearance in sonography and was found >5000. The patient underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. The serum level of beta-HCG has decreased from initially observed 188,000-0 U/ml in 4th week. The resected uterus contained an endometrial, cystic, grapelike tumor. Microscopic examination demonstrated hydropic degeneration of all the chorionic villi with trophoblastic cell proliferation consistent with a complete hydatidiform mole.To our knowledge, our case is the fourth description in the world literature of a benign complete hydatidiform mole in a postmenopausal woman. Although benign gestational trophoblastic disease generally occurs in women of reproductive age and is extremely rare in postmenopausal women, when evaluating patients who are in postmenopausal period the diagnosis of hydatidiform mole must always be considered.