Pulmonary-renal syndrome is a potentially life-threatening disorder, characterised by diffuse alveolar hemorrhage on the basis of pulmonary capillaritis in association with rapidly progressive glomerulonephritis. It can originate from various systemic autoimmune diseases. ANCA-associated vasculitides account for approximately 60% and Goodpasture's syndrome for approximately 20% of the cases. Fulminant pulmonary capillaritis can result in acute respiratory failure with the more subtle forms only being detectable by bronchoalveolar lavage. Kidney biopsy displays extracapillary proliferating glomerulonephritis and renal immunohistology facilitates detection of the underlying systemic disease. By accelerating the diagnosis of the specific underlying disease, auto-antibody testing fosters rapid initiation of treatment and thereby strongly improves the prognosis of pulmonary-renal syndrome. Intense immunosuppression with cyclophosphamide and glucocorticoids, augmented by plasmapheresis in the event of Goodpastures's syndrome, is the mainstay of therapy. Supportive measures such as temporary ventilation and hemodialysis have further reduced mortality.