Adenosarcoma of the ovary is a rare condition. We report a case of a 32-year-old patient that has been treated in our Department. The diagnosis of ovarian adenosarcoma was carried out after laparoscopy with removal of an ovarian endometriotic cyst. Laparoscopic homolateral ovariectomy was then performed and conservative treatment was decided on considering the young age, low stage and low grade of the disease. Second-look laparoscopy, clinical evaluation and ultrasound were performed for four years of follow-up. No recurrence has been detected. Conservative treatment should be proposed in fertile age with low-grade ovarian adenosarcoma, but a strict follow-up is always necessary.