This case report describes a patient who initially had a pleuritis and arthalgias. During the follow-up he developed first a membranous glomerulonephritis with nephrotic syndrome and subsequently a crescentic, rapidly progressive glomerulonephritis with glomerular basement membrane antibodies (anti-GBM). An analysis of the serum samples obtained during the follow-up revealed no infections at the onset of renal failure. However, anti-GBM could be demonstrated in the serum samples obtained 2 months before the deterioration of the renal function. The anti-GBM did not react with alveolar BM and the patient had no signs of pulmonary hemorrhage. The etiology and the sequence of the pathological events of rapidly progressive glomerulonephritis is discussed in the light of these observations.