A 64-year-old male suffered from chronic diarrhea and intermitent passage of tarry stool was reported. UGI series and panendoscopy revealed a polypoid lesion over the second portion of duodenum. Endoscopic polypectomy was done, the lesion was diagnosed as duodenal lipoma based on pathological examination. A discussion of duodenal lipoma was presented, which included pathology, symptoms, complications, diagnosis and treatment.