In the majority of cases late postoperative bleedings are intraluminal ones, showing clinical manifestations of high gastrointestinal hemorrhage. Among all bariatric procedures, this complication develops more commonly after Rouxen-Y gastric bypass. The most likely cause of such bleedings being peptic ulcer, conservative therapy with proton pump inhibitors is well justified at the initial stages of treatment. Upper endoscopy is the treatment of choice for bleeding ulcers localized in the pouch and 80% of bleedings in the pouch or gastroenteroanastomosis can be controlled in this way.If the bleeding is localized in the remnant stomach or duodenum and small intestine, more advanced endoscopic procedures are needed. Balloon enteroscopy is one of such techniques, although its efficacy in the treatment of bleeding resulting from biliopancreatic limb is extremely variable and depends mainly on specialist's skills, length of intestinal loop as well as severity of adhesions in the abdominal cavity. The article describes our experience of enteroscopy used to control bleeding from duodenal ulcer after Roux-en-Y gastric bypass intervention.