The source of blood loss remains undetermined in 5% of patients with chronic gastrointestinal bleeding. A new technique of small bowel enteroscopy with a prototypic sonde-type enteroscope 9 ft in length was used to examine 60 patients referred to the hospital with gastrointestinal bleeding of obscure origin. With an average procedure time of 6 h, the enteroscope migrated to the ileum or beyond in 77% of patients. Thirty-three percent (20 of 60 patients) had the source of blood loss identified within the small bowel at enteroscopy. Small bowel enteroscopy is a useful tool in patients with chronic gastrointestinal bleeding of obscure origin and can be considered when standard invasive and noninvasive modalities have failed to diagnose a site of bleeding.