Desquamative gingivitis is characterized by a diffuse erythema of the free and attached gingiva associated with areas of vesiculation, erosion, and desquamation. Desquamative gingivitis is not a distinct disease entity but represents a reaction pattern of the gingiva to various stimuli. Pemphigus vulgaris, cicatricial pemphigoid, and lichen planus may presents as desquamative gingivitis. We observed 3 patients whose disease was limited to the gingiva, and studied them by light and direct immunofluorescence microscope. We classified them according to clinical, histologic, and immunopathologic observations. Identification of the underlying causes of desquamative gingivitis is of utmost importance and is dependent upon clinical, histologic, and immunologic criteria.