Autoimmune bullous skin diseases, such as pemphigus and pemphigoid, may enable clarification of the mechanisms of immune regulation in the skin. Pemphigus and pemphigoid are mediated by essentially IgG autoantibodies against structural proteins of the desmosomes at cell-cell junctions and hemidesmosomes at epidermal-dermal junctions, respectively, and are characterized by blisters and erosions in the skin and/or mucous membranes. Intensive investigation over the last 3 decades has identified their target antigens and developed serological diagnostic tools as well as mouse models to help us understand their pathophysiology. Based on these advances, several new therapeutic approaches have become available, and more effective and less toxic targeted approaches are under development.