Lichen sclerosus is a chronic inflammatory mucocutaneous disease which origin remains unknown. Its prevalence ranges from one in 300 to one in 1000 of all patients referred to a dermatology clinic in the seventeenth. Through the analysis of a hospital survey, we outline the epidemio-clinical aspects of this dermatosis. Over a 19-year period (1984-2002), we have conducted a retrospective and monocentric study of all patients with genital lichen sclerosus were examined at the dermatology department of Habib Thameur hospital. Thirty-four patients suffered from lichen sclerosus. There were 33 female and only one male (sex-ratio: 0.03). All patients underwent topical corticosteroid therapy (level I, II or IV). The recovery rate of lichen sclerosus was about 20% (7/34). An epidermoid carcinoma occurred in three patients. The frequency of lichen sclerosus in our study is estimated at 1,8 new cases per year. This frequency is probably under-estimated because of some patients' reluctance to seek help. A relatively low recovery rate of genital lichen sclerosus was found in our study. This may be related to an inadequate follow up added to an insufficient treatment adherence.