Objective: To investigate the clinical and pathological characteristics and prognosis of ovarian clear cell borderline tumor. Methods: A total of 12 cases of ovarian clear cell borderline tumors recorded were collected from May 2011 to December 2017 at Obstetrics and Gynecology Hospital, Fudan University.Clinical histories were retrieved and pathological slides were reviewed. Results: The age of the patients ranged from 35 to 65 years with a mean age of 52 years. Seven cases were associated with cystic endometriosis of the ovary. All tumors consisted of irregular and crowded glands or cysts embedded in a fibromatous stroma. The cysts and glands were lined by mild to moderate atypical cells.CK7 and HNF-1β were expressed in all cases, and Naspin A was expressed in 11 cases. ARID1A expression was absent in 5 cases and p53 showed wild-type expression. None of the cases developed recurrence during follow-up ranging from 7 to 79 months. Conclusions Ovarian clear cell borderline tumor may be associated with endometriosis and tumor suppressor gene ARIDA. The tumor has a good prognosis without recurrence and progression to carcinoma.