Gastrointestinal (GI) bleeding is one of the most common encountered gastrointestinal disorders but making a precise and accurate diagnosis can be one of the most difficult tasks for the gastroenterologist. The successful diagnosis and treatment of GI bleeding requires the involvement and expertise of a variety of specialists, the use of sophisticated imaging techniques and the selection of a proper treatment modality from a variety of options. Given the requirement for a multidisciplinary approach to the diagnosis and management of GI bleeding, it is helpful to have basic common agreement among specialists as to how these patients should be diagnosed and managed. With advances in all areas of imaging and management, the treatment algorithm has significantly changed over time. In this chapter, we present current statistics on the incidence of lower GI bleeding, review the causes of GI bleeding and present an algorithm for the work-up of patients as well as the endovascular management of this problem.