A study of ninety-four patients admitted with massive lower gastro-intestinal bleeding (LGIB) is presented using a systematic diagnostic work-up including angiography, colonoscopy and various investigations, such as scintigraphy, small bowel series and ultrasonography. The bleeding source was identified preoperatively in eighty-five patients. 9 patients had a diagnostic laparotomy and a pathology was found in additional seven. No source was identified in two patients (2.1%) at exploration and "blind" subtotal colectomy was not performed in these two cases as proposed by others. We conclude that a thorough systematic assessment of patients with LGIB is important to localize the bleeding source. Exploratory laparotomy is the final step in few cases (10%) and if no intraoperative source can be identified a "blind" colonic resection should not be performed.