In the female genital tract, CD10 was initially found to be expressed in endometrial stromal tumors of the uterus as well as in mesonephric remnants and related lesions and was thought to be helpful in distinguishing these tumors from their mimics. However, new studies have shown CD10 to be expressed in a wide range of tumors of the female genital tract, making this antibody of limited diagnostic value. This review discusses diagnostic applications of CD10 in the female genital tract, with emphasis on CD10 use in mesenchymal tumors of the uterus and in the differential diagnosis of mesonephric versus non-mesonephric carcinomas, where CD10 positivity alone may be misleading in the final classification of a tumor. CD10 may be useful in establishing the diagnosis of endometriosis (with the exception of the cervix), distinguishing metastatic renal clear cell carcinoma from a primary ovarian clear cell carcinoma, and distinguishing mesonephric hyperplasia from other benign glandular proliferations of the cervix.