Endoscopic retrograde cholangiopancreatography (ERCP) and associated procedures are difficult to perform in patients with a Roux-en-Y reconstruction. Therefore, at present, at many institutions, ERCP is not generally performed for those with a Roux-en-Y anastomosis.However, double-balloon endoscopes (DBEs) have dramatically changed this situation.The use of a DBE enables an endoscopic approach into the deeply situated small intestine, which has been difficult with a conventional endoscope. Therefore, ERCP for patients with a Roux-en-Y anastomosis has been attempted using a DBE, and good results have been reported.The development of DBEs has created the possibility of performing ERCP for patients with Roux-en-Y reconstruction in whom an endoscopic approach has conventionally been believed to be difficult.