A survey of 15 elderly patients with large primary duodenal diverticula is reported. All the lesions were found on routine radiological examination and the most common presentation was diarrhoea and iron deficiency anaemia in one-third of the patients. The most frequent abnormalities were anaemia with low serum iron levels seen singly or in combination with low folate and B12levels. Two patients had steatorrhoea and two osteomalacia. Four had abnormalities in the serum protein levels. It is suggested that these deficiency states are due to stagnant loop syndrome and that it is important to look for, and treat, them in elderly patients with asymptomatic duodenal diverticulosis especially if refractory anaemia is present.