Primary ovarian squamous cell carcinoma is the one of the rarest of all ovarian malignancies. Most of them arise in mature cystic teratoma and a minority of them associated with endometriosis, arising in a Brenner tumor, or appearing in pure form. Due to its rarity, there is no agreement concerning the efficacy of postoperative treatment of primary squamous cell carcinoma of the ovary, although the prognosis of this type of tumor is much worse than that of other epithelial ovarian cancers. We describe a patient with squamous cell carcinoma of the ovary in association with ovarian endometriosis, who has undergone postoperative systemic chemotherapy.