We report a case of primary non-Hodgkin gastric stump lymphoma, found in a 78-year-old man 30 years after a distal gastrectomy for a benign peptic ulcer. The development of lymphoma in the gastric stump is rare. In fact, to our knowledge only 37 cases, including this one, have been documented. Although Helicobacter pylori is thought to be a predisposing factor, we found no histological evidence of this infection in our patient. Conversely, bile reflux and nitrite and N-nitrous compounds caused by abnormal bacterial growth in the gastric stump may play a role in inducing mucosa-associated lymphoid tissue lymphoma. The patient was treated by chemotherapy only, without surgery, which seems to be most appropriate for the early stages of this disease.