Massive ovarian edema is a rare cause of ovarian enlargement in young women. This article describes the case in a nine-year-old girl without signs of virilization or early puberty. The patient underwent laparotomy and a right oophorectomy was performed. The final pathology was massive ovarian edema. Awareness of this rare and benign lesion in young women and pediatric patients may allow a conservative management avoiding oophorectomy in some cases.