Immunoelectronmicroscopic and ultrastructural identification of the structures which bind IgA in skin of patients with dermatitis herpetiformis (DH) reveals them to be, in part, a complex of fibrillar components which are covered with amorphous substances. One of the fibers has a diameter of 80--130 A and appears to be tubular, resembling dermal microfibrillar bundles or microtubular elements of elastic fibers. The structures, at times, are associated with the dermal microfibrillar bundles and are found within an elastic fiber system which is in close proximity to the dermal-epidermal junction. Taken together, these findings suggest that the structures which bind IgA are unique to DH and might be a part of an abnormal dermal microfibrillar bundle-elastic fiber system.