Ovarian large cell neuroendocrine carcinoma (LCNC) is a rare disease that is commonly associated with a surface epithelial and germ cell neoplasm component. A 46-year-old woman presented with a pelvic mass measuring 15 cm in diameter. She underwent an exploratory laparotomy with resection of the pelvic mass. Diffuse and nodular intra-abdominal disseminations were observed. Stage III LCNC associated with squamous differentiation alone of the right ovary was diagnosed. The patient died of progressive disease 4 months postoperatively despite paclitaxel and carboplatin therapy. Ovarian LCNC associated with squamous differentiation component alone has never been reported, but its prognosis may be poor.