Accessory ovary is a rare gynecologic condition, and tumors arising in accessory ovaries are extremely rare. Accessory ovary may result from separation of migrating ovaries during embryogenesis and injuries such as inflammation and operation on normal ovary. Congenital malformations, most frequently malformations of the genitourinary organ, are seen in connection with the accessory ovary. We experienced the first case of two dermoid cysts developing in an accessory ovary located in the left infundibulopelvic ligament and another in the eutopic ovary at the same side concurrently. Here, we present this extremely rare case with a review of the literature.