Carcinoid tumors are the most common endocrine tumors of gastrointestinal tract. Argentaffin cells are the origin of carcinoids. These cells belong to the amino precursor uptake and decarboxylation (APUD) system. These cells give the tumor its most distinguishing feature: the ability to produce biogenic amines and polypeptide hormones that, in turn, give rise to the dramatic carcinoid syndrome. We treated a case of multi-centric carcinoid tumor of the duodenum in a 63-year-old male patient. He was admitted to the hospital because of epigastric pain. On the gastrofiberscopic examination, 1.0 x1.5 cm and 0.7 x0.8 cm sized two polyps (Yamada type II, I) were noticed on the duodenal bulb. The biopsy specimen showed carcinoid tumors of different histologic types. The level of 24-hour urine 5-HIAA of this case was normal. He was treated with subtotal gastrectomy with Billroth-II anastomosis. We report this case with literature review.