Dieulafoy's disease is an uncommon but potentially significant cause of gastrointestinal bleeding caused by a large-caliber arterial vessel in the submucosa, which causes erosion and debilitation of the surrounding mucosa and may lead to massive gastrointestinal bleeding. Since endoscopy may prove insufficient, echoendoscopy may help in the diagnosis of this condition. Echoendoscopy may also help improve endoscopic management using mechanical techniques (hemoclips or band ligation) or a combination of thermal techniques and injection sclerotherapy, since this allows an accurate localization of the submucosal vessel. We present a case illustrating this approach by endoscopic ultrasonography, and describe the morphological substrate of this condition.