Four cases of Laugier-Hunziker syndrome are described. In all patients (two men and two women between 39 and 57 years of age) pigmentation of the lower lip and hard palate was found. in addition, two patients had involvement of the buccal mucosa; another patient also had pigmentation of the upper lip, the gums, the soft palate, and the fingers of both hands. Histopathologic examination demonstrated an accumulation of melanin in the basal layer keratinocytes and an increase in the number of melanophages in the papillary dermis. Ultrastructural study showed the presence of numerous mature melanosomes in the cytoplasm of the keratinocytes of the basal layer and of the melanophages in the papillary dermis. Alterations of the melanocytes were not observed.