Clinical and histopatho- logical analysis of 36 cases of lichen sclerosus et atrophicus of the vulva shows that Lichen sclerosus et atrophicus can develop in the region of the vulva either as an isolated entity or, more often, with skin lesions of the same nature. What used to be called kraurosis vulvae should be regarded as an anatomo- clinical syndrome caused in the great majority of cases by lichen sclerosus et atrophicus. Lichen sclerosus et atrophicus of the vulva may become malignant, especially when there are leukoplakic plaques which often develop on the surface of the lesions.