A rare gynandroblastoma of the right ovary with a typical morphological appearance in a 65-year-old woman is reported. The tumor comprised both a granulosa cell element with a Call-Exner body and a Sertoli cell element. Pathologically, this case could be the most typical of all the world's established cases. Clinically, there were feminizing symptoms such as post-menopausal genital bleeding and endometrial cystic hyperplasia. Pre-operative serum hormonal assays indicated elevated levels of estrone, estradiol and testosterone, and low levels of gonadotropins. These returned to normal after surgery.