Sex cord tumor with annular tubules (SCTAT) is a rare ovarian neoplasm which usually occurs in two forms. In patients associated with Peutz-Jeghers syndrome, the tumors are usually small, bilateral or multifocal, and show benign clinical course. However, tumors from patients without the syndrome are often large, usually unilateral, and rarely show malignant behavior. Serous surface papillary carcinoma (SSPC) is an aggressive neoplasm which involves peritoneal linings, including ovarian surface. Recently, we encountered a case of an unusual combination of SCTAT and SSPC in the ovary of a 55-year-old Korean woman presented with abdominal distention for one year. Systemic review and physical examination were within normal limit, except for abdominal discomfort and distention. There was no stigmata of Peutz-Jeghers syndrome in all diagnostic examinations, including gastroscopy and colonoscopy. Pelvic computed tomography showed adnexal mass with multiple peritoneal nodules. Exploration revealed uterine and ovarian surfaces covered with multiple, yellow-white papillary nodules. However, the sizes of both ovaries were within normal limit. Typical serous papillary carcinomas were identified in nodules from peritoneum and ovarian surfaces. Well-circumscribed columnar epithelial cell nests composed of ring-shaped tubules encircling hyalinized basement membrane-like materials were found in the ovary away from serous surface papillary carcinoma.