With increasingly complex therapeutic gastrointestinal endoscopy comes an increased risk for complications. These complications may include bleeding, perforation, pancreatitis, infection, airway issues, and hypotension and must be both immediately recognized and appropriately managed. Skills to know how to assess and manage risk preprocedure, to know how recognize and manage serious problems that occur during endoscopy, and finally the ability to manage these issues successfully are an important part of training for endoscopy today. This chapter details relevant issues in training so as to be able recognize and manage immediate complications of therapeutic endoscopy. It covers specific risks of therapeutic endoscopy, colonoscopy, ERCP, and EUS, as well as stressing the need for planning to avoid complications in the first place. Finally, there is a discussion of the use of mock "situations" and simulations of complications, such as perforation and bleeding. Such drills and simulations allow for training in the management of complications associated with therapeutic endoscopy prior to their occurrence in an actual patient.