Endoscopic retrograde cholangiopancreatography involves endoscopic visualization of the papilla of Vater, placement of a cannula in the orifice of the papilla and contrast radiology of pancreatic and biliary ducts. With experience, the procedure can be performed relatively rapidly with visualization of the desired duct in the majority of patients, and a low frequency of complications. The technique appears to be highly sensitive and specific for the diagnosis of biliary and pancreatic disease. Valuable additional information may be obtained from duodenal endoscopy, duodenal biopsy and duct aspiration for cytological studies. An extension of the technique--endoscopic sphincterotomy of the papilla of Vater--has become a therapeutic option in selected patients with choledocholithiasis.