The destruction of melanocytes is the cause of depigmented maculae that clinically represent the disease vitiligo . Although the cause is unknown, various theories such as the autoimmune, autocytotoxic, and neural hypotheses have been proposed. Extensive research has provided numerous answers regarding the pathogenesis, histopathologic evidence, and treatment of vitiligo. This discussion of vitiligo summarizes the varied clinical presentations of the disease, theories attempting to explain the mechanism of melanocyte destruction, histopathologic findings, and different treatment modalities currently available. (J Am Acad Dermatol 1998;38:647-66.) Learning Objective: At the conclusion of this learning activity, participants should be familiar with the clinical and histopathologic presentations of vitiligo, the etiologic hypotheses of the disease, and the treatment options.