The case history of a 34-year-old patient with precirrhotic idiopathic haemochromatosis and severe chronic steatorrhoea is presented. The pancreas had a normal appearance on ultrasonography and endoscopic retrograde pancreaticography. However, pancreatic function tests revealed significant abnormalities. The pancreatic output of trypsin, amylase, lipase and bicarbonate was deficient and basal and stimulated serum pancreatic polypeptide levels were subnormal. In contrast, the oral glucose tolerance test was unimpaired. The pancreatic insufficiency had started suddenly during a summer vacation and may have had a viral aetiology. The hypothesis is advanced that in haemochromatosis the iron-laden pancreatic acinar and PP-producing cells are more susceptible to damage by viruses than normal pancreatic cells.