Backgrounds and Aims: Endoscopic examination of the afferent limb, or choledocho-jejunostomy, in patients with various surgical reconstructions of the gastrointestinal tract, such as Roux-en-Y anastomosis or Billroth II gastrojejunostomy, is often extremely difficult due to anatomical characteristics and intestinal adhesion. Although the advent of video capsule endoscopy facilitated the observation of the entire small bowel, one of the limitations of this new technology includes the difficulty of accessing the surgically reconstructed gastrointestinal tract. Double-balloon endoscopy (DBE) (Fujinon, EN-450P5/20, EN-450T5/20, Fuji Photo Optical Co., Ltd., Saitama, Japan) facilitates the selective inspection of discrete intestinal regions, and allows for timely endoscopic treatment of disorders heretofore requiring surgical intervention. In this study, we evaluated the efficacy of double-balloon endoscopy in patients with surgically reconstructed gastrointestinal tracts. Patients: A total of 130 patients underwent 200 DBE examinations between Jun. 2003 and Nov. 2005 at Nippon Medical School Hospital, Tokyo, Japan. Among them, 12 consecutive patients with surgically reconstructed gastrointestinal tracts were enrolled. The median age of these 12 patients was 65.3 (30-81); 6 men and 6 women. The surgical procedures of these patients included Billroth II gastrojejunostomy in 5 patients, Roux-en-Y anastomosis in 3 patients, pancreatoduodenectomy in 3 patients, and blind loop with side to side anastomosis in 1 patient. Results: DBE could reach the cecum of the afferent loop in 10 of 12 patients (83.3%), with endoscopic access and direct observation successfully carried out in all these 10 patients. Cholangiocellular carcinomas were found in 2 patients, choledocholithiasis in 2 patients, and 4 patients underwent the procedure for endoscopic retrograde cholangiography (ERC). Anastomotic stricture after Roux-en-Y anastomosis was found in 1 patient who had been suffering from symptoms of ileus. A detachable stent was placed at the stricture, and clinical symptoms improved. No complications were encountered during and after any of these procedures. Conclusions: DBE is a very useful and safe tool for the diagnosis and treatment of lesions in the surgically reconstructed gastrointestinal tract. It may also preclude unnecessary surgical intervention in certain cases.