Sertoli-Leydig cell tumors of the ovary are rare neoplasms of young women and are best known for their frequent virilizing effects. They have very rarely been reported in association with other ovarian neoplasms. We report such a tumor associated with a mature cystic teratoma in the same ovary. The wide variety of histologic patterns seen in many Sertoli-Leydig cell tumors including the present case, often causing difficulty in diagnosis, is reviewed.