Balloon enteroscopy is a method that allows endoscopic inspection of the entire small bowel, or large parts of it, while simultaneously making it possible to obtain histologic samples and carry out treatment measures. Studies of double-balloon enteroscopy (DBE) have confirmed the high diagnostic yield of the procedure, with an acceptably low complication rate (approximately 1% for diagnostic DBE and 3% to 4% for therapeutic DBE). The principal indication for the procedure is midgastrointestinal bleeding, that is, when the bleeding source is located in the small bowel. With good patient selection, the diagnostic yield here is 70% to 80%, and this has a substantial influence on subsequent treatment measures. Single-balloon enteroscopy appears to be a simplification of the technique that is easier to handle, but few original studies have been published on the topic to date, and the results of prospective and controlled studies with larger numbers of patients must therefore be awaited. At present, DBE must still be regarded as the standard method for diagnostic and therapeutic endoscopy in the small bowel, avoiding the need for intraoperative enteroscopy or therapeutic laparotomy.