The clinico-pathological features of one rare case of an ovarian tumor of probable Wolffian origin are reported. This tumor arises within the rete ovarii and is predominantly cystic on gross examination. Microscopically these cysts are lined by flattened epithelial cells and are separated by solid areas formed by large tubular glands. It is difficult to recognize this type of tumor on frozen section and to distinguish it from adenocarcinoma of the ovary. Surgery can be limited to total hysterectomy and bilateral salpingo-oophorectomy. No adjuvant therapy is necessary.