A78-year-old female was admitted to our hospital with anorexia due to ascites. We were not able to diagnose by cytological diagnosis. For a definite diagnosis she underwent an open biopsy. Histological findings revealed observable papillary adenocarcinoma with psammoma body, carcinoma cells were positive for Ber-EP4 on immunostaining, and ovaries were normal. Thus, we made a diagnosis of peritoneal serous papillary adenocarcinoma. She was treated by intraperitoneal administration of CDDP(20 mg/day: day 1, every four weeks). Ascites vanished and CA125 was within the normal range. There was no recurrence after 3 years, but Virchow's lymph node metastasis occurred. The patient is still alive 12 months after metastasis with CDDP intraperitoneal administration.