The endoscopic findings in six patients with carcinoid tumor of the duodenum were analyzed. Radiographic and endoscopic examinations revealed a smooth and round elevation (measuring 5-20 mm in diameter) in the duodenal bulb. In three patients, the lesion was accompanied by an irregularly shaped erythematous depression, a characteristic endoscopic finding of this tumor. Because the endoscopic forceps biopsy technique led to an accurate diagnosis, we wish to stress the clinical value of the endoscopic modalities.