Small bowel diverticulosis is an uncommon and often asymptomatic condition that is sporadically observed during radiographic examination or laparotomy. Although it is frequently seen in duodenum, jejunal and ileal locations are very rare. The majority of patients with jejunal diverticula have no symptoms. However, they can present with a number of acute and emergent complications with a high rate of mortality. Bleeding from jejunal diverticula occurs in less than 3% - 8% of patients and often present as fresh rectal haemorrhage. This can confuse the clinician since a bleeding source in colon is far more common. We report a patient with acute massive rectal bleeding. Abdominal CT angiography demonstrated a jejunal diverticulum as the bleeding source and the patient underwent resection of the affected segment. She has since remained free of gastrointestinal bleeding.Although jejunal diverticulosis is rare, it is an important differential diagnosis for patients with gastrointestinal haemorrhage of unknown origin as it may cause extensive rectal bleeding. Abdominal CT angiography can localize the bleeding source and resection of the affected bowel and primary anastomosis is the treatment of choice.