Junctional blister formation is the common feature of four clinically different types of inherited epidermolyses with atrophies but lack of scarring which, as a group, have been termed epidermolysis bullosa atrophicans. The Herlitz type is the most common one among them. Based on a material of 24 cases aged 2 days to 42 years at the time of biopsy, ultrastructural data on the pathomorphogenesis are reported. Blisters form in the dermo-epidermal junction area between the basal lamina and the basal cell plasma membrane. A well-developed basal lamina-anchoring fibrils complex covers the blister floor. Hypoplasia of hemidesmosomes precedes blister formation and is a constant finding in intact junction area without any other signs of disturbances. It is, therefore, regarded as a causal factor in the pathogenesis. Nail loss as a result of junctional separation within the nail bed, secondary changes in older blisters and formation of slowly healing granulation tissues are also reported.--Early diagnosis is made available by electron microscopy as shown in out early childhood cases. Genes coding for junctional epidermolyses seem to be far more frequent than those coding for the scarring or dystrophic types.