The epidermal basement membrane is a specialized structure localized between the epidermis and the dermis. Recent studies have elucidated the biological roles of the basement membrane and its pathophysiological involvement in bullous diseases. To understand the functions of the basement membrane, it is essential to have clear and precise information regarding the ultrastructural molecular organization of the epidermal basement membrane. Immunoelectron microscopy is a powerful technique and the only method available for the clarification of the ultrastructural localization or orientation of molecules. This review summarizes the latest information regarding the molecular organization of the epidermal basement membrane as determined by immunoelectron microscopy as well as the blistering diseases that occur in the epidermal basement membrane zone.