Brunner's Gland Hamartoma (BGH) is a benign tumor of the duodenum that can lead to gastrointestinal bleeding and intestinal obstruction. Endoscopic resection has seldom been reported. We describe the case of a duodenal obstruction caused by a large BGH (6 cm x 4 cm). We report a 57-year-old woman hospitalized for tarry stools, weight loss and anorexia. Endoscopy revealed a large BGH (6 cm x 4 cm). Endoscopic ultrasound (EUS) revealed a submucosal duodenal tumor. In this paper, we report a case of large hyperplasia of BGH, successfully treated by endoscopic technique.