Carcinoma of the duodenum, although uncommon, can be diagnosed by direct visualization, photography of the tumour and biopsy by the fibre-duodenoscope. The duodenoscopic examination may not only distinguish carcinoma of the duodenum from pancreatic carcinoma, ampullary carcinoma and secondary tumour from an adjacent organ but will also enable a correct diagnosis to be made early in the course of the disease. It is therefore suggested that duodenoscopy and biopsy will increase the resectability and 5-year survival rate.