A 61-year-old male patient suffering from squamous cell carcinoma of the lower lip developed pemphigus vulgaris two months after exposure to radiotherapy. Skin lesions were initially localised to the face and neck and later extended over other skin areas. The eruption are improved with glucosteroid therapy, which were stopped after six months. Pemphigus induced by radiotherapy is rare, latency before the onset of the vesiculobullous eruption is variable. Clinical, histological and immunological characteristics are similar to those of other types of pemphigus.