The authors report the case of a 40-year-old woman, who was operated for an ovarian mucinous cystadenocarcinoma. The pathologic findings of the hysterectomy specimen with bilateral salpingoophorectomy showed an ovarian mucinous cystadenocarcinoma associated with an endometrioid adenocarcinoma of the uterine cervix. The mucinous cystadenocarcinoma represents the third most common type of ovarian carcinoma. In the literature, this tumor had been found in association with endocervical adenocarcinoma or with minimal deviation adenocarcinoma (adenoma malignum) of the uterine cervix. However, its association with an endometrioid adenocarcinoma, to our knowledge, has not been reported.