ANCA disease remains a subject of great experimental and clinical interest. The subcategories of names and descriptions for this collection of vasculitides and necrotizing glomerulonephritides is still a subject of some debate. The various forms of ANCA disease share some characteristics, and similar therapies are often recommended for overlapping categories of disease. The immunopathogenic effects of myeloperoxidase and proteinase 3 antibodies are well established, and good mechanisms for initiation of disease are starting to emerge, particularly the role of autoantigen complementarity. Here we examine these various topics and discuss an approach to treatment.