Dieulafoy's lesion is a rare cause of repetitive and massive gastrointestinal bleeding, and this is characterized by an isolated arteriole protruding through a small mucosal defect. Dieulafoy's lesion is generally found in the stomach within 6 cm of the gastroesophageal junction, and usually on the lesser curvature, but many lesions have been reported in extragastric locations, including the esophagus, small bowel and rectum. A Dieulafoy's lesion in the ampulla of Vater is extremely rare, and only one such case has been reported in the Korean population. We experienced a rare case of Dieulafoy's lesion in the ampulla of Vater with massive pulsatile bleeding, and this was successfully treated by transparent cap-assisted endoscopic hemoclipping. We report here on this case with a review of the relevant literature.