Clear cell and endometrioid tumors are subtypes of Müllerian epithelial tumors that can arise throughout the gynecological tract, mainly including the uterus as well as the ovary. These subtypes of primary ovarian tumors include benign, borderline and malignant counterparts as opposed to other Müllerian sites where these tumors usually present as malignant neoplasms (carcinomas). A strong association with endometriosis has been established with the histogenesis of these tumors in a large subset, while in other cases, adenofibromatous lesions seem to be the primary origin of these tumors. The current chapter covers the clinicopathologic features of these endometriosis-associated histotypes of ovarian carcinoma. New updates include seromucinous carcinomas that now are a subtype of endometrioid carcinomas of the ovary as well as the likelihood that many cases of synchronous carcinomas, usually of endometrioid type, have an origin in the endometrium, determined by molecular and genetic type studies.