Granulomatosis with polyangiitis (GPA, formerly Wegener’s granulomatosis) and microscopic polyangiitis (MPA) are associated with the detection of antibodies against neutrophilic cytoplasmic antigens (ANCA) and are referred to as ANCA-associated vasculitides (AAV). In the event of the clinical suspicion of AAV the ANCA should first be determined by means of an antigen-specific immunoassay for proteinase 3‑ANCA and myeloperoxidase-ANCA, according to current consensus recommendations. The diagnosis of AAV should also be confirmed by biopsy if possible. The classification criteria for AAV are currently being revised. Diagnostic criteria do not exist. The standard induction therapy consists of rituximab or cyclophosphamide, each in combination with glucocorticoids (GC). In the absence of severe organ involvement, methotrexate can alternatively be used. Recent study data suggest that additive plasmapheresis does not improve the long-term outcome. After remission, remission-preserving treatment with azathioprine, methotrexate or rituximab should be given for at least 48 months. The risk of severe infections is markedly increased, especially during the remission induction phase but can also be reduced during treatment with rituximab by the prophylactic administration of trimethoprim-sulfamethoxazole. In view of the increased risk of infection, GC-reduced or GC-free treatment regimens are currently the focus of clinical development.