Endosalpingiosis is a disorder of the Mullerian system characterized by benign glands lined with tubal type epithelium and involves the peritoneum, subperitoneal tissues and retroperitoneal lymph nodes. Myometrial endosalpingiosis is very rare. A 44-year-old female presented to the hospital complaining of menorrhagia. Gynecological and radiologic examination revealed a pelvic mass 7.5 cm in diameter, suggestive of a leiomyoma with secondary cystic changes. The gross examination showed an intramural large cyst within the right fundic wall of the uterus. Microscopically, the cyst consisted of multiple micro-macro cysts lined with benign tubal epithelium. With these findings, the diagnosis was cystic endosalpingiosis. In this report, the clinicopathologic features of a cystic endosalpingiosis case located in the myometrium was presented with a review of the literature.