Therapeutic ERCP was born with the introduction of endoscopic sphincterotomy (ES) in 1973, which transformed the therapeutic approach to biliary disease, especially the management of common bile duct (CBD) stones. Today, more than 150,000 endoscopic biliary sphincterotomies are performed annually in the United States. Patients with bile duct stones present with a variety of clinical problems, alone or in combination, including cholestasis, pain, cholangitis, pancreatitis, or as asymptomatic demonstration on imaging or operative cholangiography. It has become increasingly feasible, acceptable, and supportable to treat patients in all these categories endoscopically. In its infancy, endoscopic therapy was initially considered justifiable only in elderly patients after cholecystectomy who had recurrent or retained CBD stones and who were at high risk of serious complications from open surgical CBD exploration or reexploration at a time when few endoscopy centers could offer the techniques. Adolescence witnessed the impressive successes of ES and stone extraction methods in high-risk groups. With an expansion of units offering endoscopic therapy, a low level of associated complications, and a strong patient preference, many centers were persuaded to widen their indications for the procedure to include younger patients after cholecystectomy, and later, a range of patients in whom the gallbladder was still in place but in whom CBD stones were the principal clinical problem. Much of this occurred in the absence of any comparative trial data to aid decision-making and, indeed, there was such enthusiasm for endoscopic therapy that the establishment of randomized trials became difficult. Nevertheless, the wisdom of maturity dictated that, because they are essential to settle arguments about relative morbidity and mortality risks in different patient populations and the bias of selection for treatment by endoscopic or surgical means, such prospective studies were forthcoming and have provided a sound basis on which to triage patients. Concomitant with the developments of wider clinical application has been the evolution of endoscopic techniques to reduce stone size and facilitate endoscopic removal. These comprise mechanical lithotripsy, laser lithotripsy, and electrohydraulic lithotripsy (EHL). There was a growing appreciation that maintaining biliary drainage was imperative after any endoscopic intervention and could be achieved by nasobiliary tube or endoprosthesis. Many lithotripsy techniques can also be applied by means of percutaneous choledochoscopy, which may be the only endoscopic option if the peroral route is denied or fails. The endoscopist is now faced with the referral of a number of clearly defined groups of patients with confirmed or suspected bile duct stones for whom endoscopic therapy may be optimal compared with these alternatives: 1. Severe cholangitis with or without cholelithiasis; 2. Severe gallstone pancreatitis;