The surgeon is frequently involved in the management of patients with occult gastrointestinal bleeding. It is important to have a systematic approach to these patients to avoid the "looking for a needle in a haystack" approach to this problem. These are a group of patients who have undergone extensive standard gastroendoscopic evaluation and continue to bleed. Five percent of gastrointestinal bleeding occurs between the ligament of Treitz and the ileocecal valve. Therapeutic management may be guided by the age of the patient. Patients aged younger than 50 years will usually bleed from readily identifiable palpable lesions, such as leiomyoma, Meckel's diverticulum, or other small-bowel tumors, whereas the patients aged older than 50 years most commonly bleed from angiodysplasias or arteriovenous malformations that are not palpable, frequently multiple, and may be evanescent.