Over the past 20 years, bile aspiration at endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography has been developed for cytological diagnosis of biliary tract stricture. This safe and specific test has allowed a diagnosis to be reached before or without operation in about one-third of malignancies of the pancreas or biliary tree. The recent development of biliary brush cytology has produced better results. An endobiliary biopsy forceps is now available that may allow safe sampling of lesions causing extrinsic compression of the biliary tract. An endobiliary aspiration cytology needle has been produced that may permit non-ulcerating lesions to be diagnosed. A safe alternative to endobiliary methods is percutaneous fine-needle aspiration cytology; this yields a diagnosis in about half of patients presenting with obstructive jaundice and an imaged mass lesion.