Lichen sclerosus et atrophicus (LSA) is a relatively rare dermatosis of unknown etiology. The disease is clinically characterized by white, macular lesions on the skin, and is usually associated with an atrophic condition affecting the vulva and peri-anal skin. Involvement of the oral mucosa with or without concurrent genital or skin lesions has been reported only occasionally in the literature. In the present paper two new cases of oral LSA are presented, which were, in fact, the only manifestation of the disease. Furthermore, the epidemiologic, etiologic, clinical and histopathologic aspects of oral LSA are discussed.