ERCP is a complex diagnostic procedure requiring manual dexterity, careful attention to endoscopic and radiographic technique, and correct interpretation of the resulting images. Not surprisingly, the procedure is associated with many potential pitfalls. Many of these are related to normal anatomic pancreatic and biliary variants and to artifacts associated with the examination itself. Knowledge of these variants and artifacts is necessary to perform procedures and interpret the results effectively. Our discussion and illustrations are based on a retrospective review of approximately 1300 ERCP studies performed at a single center during a 2-year period.