Endoscopic retrograde cholangiopancreatography, endoscopic sphincterotomy, and endoscopic biliary drainage have dramatically changed the diagnosis and management of disorders of the pancreas and hepatobiliary tract. Endoscopic retrograde cholangiopancreatography will provide a high-resolution study that will define accurately the nature and location of the disease process involving the pancreas or bile ducts. Although sonography, CT, and, recently, MRI may provide clues to the diagnosis, it often remains for endoscopic retrograde cholangiopancreatography to establish the diagnosis with certainty. Endoscopic sphincterotomy has been invaluable in the management of common bile-duct stones. In patients who have had their gallbladders removed, sphincterotomy has avoided reoperation in the same field and the risk of general anesthesia. Sphincterotomy also is assuming an increasingly important role in the management of common-duct stones in patients with their gallbladders in situ who are poor operative candidates. In these patients, sphincterotomy likewise avoids the risk of general anesthesia and the surgical stress of opening a major body cavity. The technique has also proved to be helpful in the palliative treatment of ampullary and distal common bile-duct carcinomas in those patients who are poor operative candidates. Finally, sphincterotomy has found a role in the treatment of choledochal cysts and may provide relief of pain in those patients with the elusive diagnoses of postcholecystectomy syndromes, biliary dyskinesias, and sphincter of Oddi dysfunction. Endoscopic biliary drainage is becoming an increasingly popular option for the palliation of malignant biliary obstruction. In those patients who are poor operative candidates, the risk of general anesthesia and major surgery is avoided. In those patients with obviously incurable tumors, endoscopic drainage allows for a brief hospitalization without surgery in the face of a short life expectancy.