Two cases of Goodpasture's syndrome with severe pulmonary haemorrhage and normal renal function are described. In spite of minor (patient 2) or even no (patient 1) biological or light microscopic signs of glomerulonephritis, immunofluorescence of immunoglobulin G (IgG) was strongly positive in a linear fashion along the glomerular basement membranes in both patients. We suggest that renal biopsy in patients with apparently idiopathic pulmonary haemorrhage may lead to an early diagnosis of Goodpasture's syndrome. It is not possible in this disease to recognize on presentation those patients who will remit spontaneously and those who will undergo severe disease. The deadly evolution for patient 1 and some cases in the literature lend support to the notion that cytostatics and plasma exchange must be added to corticosteroids, even if pulmonary haemorrhage is not active and renal function is normal at the time.