Cancer of the bile duct system may arise in any part of the biliary tract — from the intrahepatic biliary radicles to the inflow into the duodenum. Cholangiocarcinoma — the tumour derived from bile duct epithelium — originating from the intrahepatic ductal system may be symptomatically and clinically indistinguishable from other solid liver lesions, whereas tumours located in the pancreatic and ampullary region represent a heterogeneous group which may originate from the true periampullary tissues, the pancreas, the duodenal mucosa or the common bile duct. Thus, this chapter will deal with primary malignant tumours of the left and right hepatic ducts and their confluence, the common hepatic and bile ducts above the pancreas, and with tumours originating in the gallbladder and cystic duct.