ANCA-associated vasculitides (AAV) include primary vasculitides that affect predominantly small vessels such as Wegener's Granulomatosis (WG), Microscopic Polyangiitis (MPA) and Churg-Strauss Syndrome (CSS). The former is closely associated with cANCA, induced by proteinase 3, MPA is characterized by pANCA with MPO specificity and the latter, CSS, can--to a far lesser extent--be associated with, either c- or pANCA. All AAV have in common (as opposed to immune-complex-vasculitides) that they occur without complement consumption and show histologically no deposition of immune complexes (pauci-immune vasculitis). Clinically, the AAV show quite variable courses. The mostly clinically rather inapparent initial phase, which is typically granulomatous in WG and CSS, is mostly followed by a potentially life-threatening phase of full blown generalized systemic vasculitis. Frequently, rheumatic complaints are the initial symptom. The characteristic clinical features in the full blown generalized vasculitis are mostly found in the upper respiratory tract, the lung and/or the kidney. Subsequently, the clinical pictures of AAV will be described, especially taking into consideration the rheumatic manifestations as early symptoms. Furthermore, pathodynamics and differential diagnoses of AAV will be regarded.