Desquamative gingivitis is believed to be a clinical sign of certain mucocutaneous diseases rather than a distinct pathologic entity. The prevalence of desquamative gingivitis was studied in a group of patients with the most common mucocutaneous diseases. Of 414 patients with pemphigus vulgaris, mucous membrane pemphigoid, or oral lichen planus, 49 (11.8%) exhibited gingival lesions in the form of desquamative gingivitis. Desquamative gingivitis was most prevalent in the patients with mucous membrane pemphigoid (41.6%) followed by those with pemphigus vulgaris (9.1%). Other clinical characteristics, as well as histopathologic and immunohistochemical findings, that aid in early diagnosis are presented.