Radiation induced pemphigus, as an example of induced pemphigus, is a rare disease which occurs in patients receiving radiotherapy. A 56-year-old male patient with nasopharyngeal cancer received 3 cycles of chemotherapy and radiotherapy on the neck and anterior chest areas. One month after completion of radiotherapy, eroded and crusted areas developed within the irradiation site. In spite of systemic antibiotic treatment, the skin lesions persisted and spread further to the trunk and upper extremities with new crops of bullae. He was treated with a high dose of prednisolone and the skin lesions cleared. We discuss the suggestive pathogenesis of radiation-induced pemphigus with the comparative results of immunoblotting in various variants of pemphigus. (Ann Dermatol 10:(3) 212-215, 1998).