Brunner's gland adenoma is a rare benign tumour of the duodenum. Less than 200 cases have been reported in the literature. Usually asymptomatic, these lesions rarely manifest as upper gastrointestinal haemorrhage or duodenal obstruction. We report a 40-year-old gentleman who presented with melaena and iron deficiency anaemia. Duodenoscopy revealed a large pedunculated tumour in the duodenal bulb. Due to the huge size, the patient underwent surgical polypectomy through laparotomy and duodenotomy. Histological examination confirmed it to be Brunner's gland adenoma. Endoscopic and radiological features are illustrated along with a literature review of this rare, yet important and easily overlooked cause of gastrointestinal haemorrhage.