The primary vasculitides are autoimmune diseases often characterized by the presence of autoantibodies. These antibodies can help in correctly diagnosing patients (e.g. antineutrophil cytoplasmic antibody [ANCA] associated vasculitis) and in monitoring patients during follow-up. Also, they provide insight in the underlying pathogenic processes and therefore may be instrumental in developing improved treatment options. This chapter describes current knowledge on the presence of autoantibodies in different vasculitic diseases with a focus on PR3-ANCA, MPO-ANCA, anticomplementary proteinase 3 (anti-cPR3) antibodies, antilysosomal membrane protein-2 (LAMP-2) antibodies and antiendothelial antibodies (AECA). Furthermore, we discuss the pathogenic potential of these autoantibodies and their (potential) therapeutic implications.