Two cases of epidertnoid cyst of the ovary are added to the ten reported in the literature. This rare lesion is usually an incidental finding. Its main interest is in its histogenesis, which includes metaplasia of the coelomic surface epithelium, monophyletic development of teratoma, and metaplasia of the rete ovarii. We investigated two cases of epidertnoid cyst. Histologic examination of the cysts showed a thin lining of mature keratinizing squamous epithelium rectum: unaccompanied by skin appendages or other teratomatous elements.