Direct and indirect immunofluorescence (IF) plays a role in the evaluation of immunobullous diseases and their mimics, and in the investigation of vascular injury syndromes and autoimmune connective tissue disease (CTD). IF mapping may be an important adjunct in the assessment of congenital epidermolysis bullosa syndromes and in Alport disease, in which antibodies are directed at certain components of the basement membrane zone to assay for their deficiency. In many cases of immunobullous and autoimmune CTDs, correlation with direct IF results is useful and often decisive in lesional evaluation and thus in patient management.