Bleeding from small bowel is a quite rare event and often is a diagnostic challenge to physician and surgeon. We present a case of a patient with an acute massive haemorrhage due to jejunal diverticulosis and with an unusual clinical setting. The site of bleeding was localized by scan with radiotagged erythrocytes, but the diagnosis of jejunal diverticule was evident only at laparotomy. The patient underwent to surgical resection of the affected bowel (40 cm). Although jejunal diverticula are considered a rare source of gastrointestinal haemorrhage, we suggest that this disorder must be considered in all patients with occult gastrointestinal bleeding especially in the elderly.