Antiglomerular basement membrane disease is an autoimmune disorder characterized by the presence of antibodies directed against glomerular basement membrane. Pyrexia of unknown origin (PUO) is defined as temperatures higher than 38.3 degrees C on several occasions, with a duration of more than 3 weeks, and failure to reach a diagnosis despite 1 week of in-patient investigation. There is a large list of causes of PUO including infections, malignancies and autoimmune diseases, but antiglomerular basement disease has not been described as a cause. We present the first case of antiglomerular basement disease which presented with PUO.