Reports of pemphigus following ionizing radiation exposure are rare. We report two cases and review the literature regarding this association. Characteristics common to these cases include a prodromal persistent nonspecific dermatitic eruption that is often interpreted as radiation dermatitis, and latency of variable duration before the onset of a vesiculobullous eruption that begins at the portal of irradiation. Direct immunofluorescence is positive for intercellular IgG, while indirect immunofluorescence is commonly positive only at low titers; HLA correlations have not been studied. Documentation of clinical course and laboratory confirmation of the diagnosis, including hematoxylin-eosin, direct and indirect immunofluorescence, and HLA determinations (if available), should be recorded to enable further clarification of this entity.