The authors describe a case of 60-year-old man with primary adenocarcinoma of the distal duodenum. The first, ex post assumed symptom, was haemorrhage into the gastrointestinal tract almost two years before the final diagnostic conclusion. The diagnosis was not correctly established even during subsequent examinations during progression of the disease and not even during the first surgical revision. The reason is, no doubt, the rareness of the diagnosis and the adverse site of the tumour. An asset was was enteroscopy, although its conclusion was not accurate as regards the site. The tumour was radically removed only during the second operation by segmental resection of the distal duodenum with a duodenojejunal anastomosis in the region of D2. The patient was then referred to the care of an oncologist. The case shows the diagnostic difficulties and the unique operation that was performed. Possible success of treatment is always conditioned by coordinated gastroenterological, surgical and oncological care.