Tumors of the biliary tract can usually be diagnosed by conventional cholangiography, either via endoscopic retrograde cholangio-pancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC). However, these procedures do not precisely delineate the segmental anatomy of the intrahepatic bile duct and the extent of cancer spread into the bile duct wall. Since 1975, we have been using selective cholangiography via percutaneous transhepatic biliary drainage (PTBD) and with the aid of percutaneous transhepatic cholangioscopy (PTCS) to achieve accurate preoperative diagnosis of tumor extension. PTBD was performed in 501 malignant cases, with 295 of them undergoing PTCS; high-quality cholangiograms were obtained in all cases. PTCS offers the additional diagnostic advantage of taking biopsies for the preoperative diagnosis and staging of biliary tract cancer. The morbidity and mortality rates of PTBD and PTCS were 9% and 0%, respectively.