The technique and the anatomy of the bile duct and pancreatic duct will be described. Anatomical variants of the biliary duct and the pancreatic duct system will be analyzed and their possible role in generating diagnostic imaging pitfalls, will be described. Strategies to avoid pitfalls in diagnostic imaging of the bile duct and the pancreatic duct system will be illustrated, considering the possible source of pitfalls. Diagnostic imaging findings of different diseases involving the biliary ducts and pancreatic duct system will be illustrated, as well as the diagnostic imaging criteria useful for the differential diagnosis.