Pancreatitis is the most frequent complication after endoscopic retrograde cholangio-pancreatography (ERCP) with an incidence of 3.5% in unselected patients. Post-ERCP pancreatitis appears unavoidable even in the hands of expert endoscopists. Consequently, attempts to reduce the rate of this complication by different cannulation techniques and/or pharmacological intervention should be pursued. A web-based registry for the procedure will be created to record multiple aspects of ERCP. Multiple national and foreign centers will be invited to participate in data collection and analysis to clarify the role of different factors which influence the outcome in the first phase. Interventional prospective multi-center trials will be initiated using the registry in the second phase of the project with the aim to improve the outcome.