A 76 year old white woman died from massive pulmonary haemorrhage nine days after she was admitted to Parkland Memorial Hospital for evaluation of haemoptysis and rapidly progressive glomerulonephritis. The differential diagnosis of haemoptysis with rapidly progressive glomerulonephritis is presented with particular emphasis on Wegener's granulomatosis and microscopic polyarteritis. Necropsy showed a small vessel necrotising vasculitis associated with a focal segmental necrotising glomerulonephritis consistent with microscopic polyarteritis.