The purpose of this study is to describe the feasibility of using single-balloon enteroscopy (SBE) to perform endoscopic retrograde cholangiopancreatography (ERCP) in patients who had a prior Roux-en-Y (RY) anastomosis. This case series describes four patients, one with RY gastric bypass, two with RY due to bile duct injury, and one with RY after liver transplantation, who underwent ERCP with SBE. Cholangiography was successful in three of the four patients. In the procedure that was not successful, the enteroenterostomy site could not be located. The successful procedures ranged from 65-91 min in duration. Medication doses were higher than with typical ERCPs. No procedural complications occurred. SBE for ERCP is a feasible option for endoscopic access to the biliary tree in patients with prior RY anastomoses. Limitations of this technique include the time requirement, delay in identification of the enteroenterostomy site, potential learning curve, and immature technology lacking accessories.