Dieulafoy lesions, a rare cause of gastrointestinal hemorrhage, are caliber-persistent submucosal arteries without surrounding ulcers or mucosal lesions. Dieulafoy lesions rarely bleed profusely and may be missed during diagnostic endoscopy. Most of these lesions are located in the stomach; they have been reported only rarely in other parts of the gastrointestinal tract, including the small bowel. We report a case of gastrointestinal hemorrhage secondary to a Dieulafoy lesion in the afferent limb of a Billroth II gastric bypass.