A 73-year old man presented with abdominal pain. A tumor with central ulceration was observed in the ileum using double-balloon enteroscopy. Histological findings of the biopsy specimens were consistent with malignant lymphoma. Double-balloon enteroscopy confirmed the diagnosis of a malignant lymphoma tumor which was surgically resected. The patient is still in complete remission now. A 73-year old man presented with abdominal pain. A tumor with central ulceration was observed in the ileum using double-balloon enteroscopy. Histological findings of the biopsy specimens were consistent with malignant lymphoma. Double-balloon enteroscopy confirmed the diagnosis of a malignant lymphoma tumor which was surgically resected. The patient is still in complete remission now.