Cholangiocarcinoma is the term applied to primary malignant tumours of the biliary tract. They are categorised according to site into intrahepatic, gallbladder, hilar and distal bile duct cancers. The incidence of bile duct cancer in autopsy series ranges from 0.01% to 0.46%.1 Despite its low occurrence, the diagnosis of cholangiocarcinoma should be considered in every case of obstructive jaundice. There is increasing evidence that suggests a steep, fourfold rise in the incidence of this condition over the last few decades; in particular intrahepatic cholangiocarcinoma now accounts for more deaths than hepatoma in the Western countries.2 Cholangiocarcinoma has the potential to be diagnosed early, when it is small, localised, and amenable to an aggressive treatment approach. This chapter will concentrate on hilar bile duct cancers. Peripheral intrahepatic cholangiocarcinoma and gallbladder cancer will also be considered as closely related conditions that are diagnosed and managed in a similar way to hilar tumours. In contrast, carcinomas of the distal common bile duct present diagnostic and therapeutic problems more similar to carcinoma of the head of pancreas and are best considered with this condition.