Carcinoid tumors are slow growing submucosal tumors with metastatic potential that arise from enterochromaffin cell. The annual incidence of carcinoid tumor is 2 to 3 per 100,000. Carcinoid tumor of duodenum is very rare with an incidence of about 8% among gastrointestinal carcinid tumor. As a endoscopic examination and immnohistochemical stain are developed, an rate of detection is increasing. Among the possible factor of metastatic prediction, tumor size＞10 mm, central depression or ulcer, invasion below submucosa, lymphatic or venous invasion are associated with higher metastatic potential. Specially, in case of tumor size＜10 mm, in duodenum, there is no report of metastasis to liver in Korea. But, recently, we experienced a rare care of duodenal carcinoid measured by less than 10 mm with liver metastsis. Thus, we report here this case with a review of literature. (Korean J Gastroenterol 2009;53:246-250)