We report the rare clinical case of perforation and delayed penetration of an ulcer at the gastro-jejunal anastomosis following 14 months after laparoscopic one anastomosis gastric bypass in a young female patient. No significant ulcer predictors at baseline: a chronic ulcer formed within the first six months after one anastomosis gastric bypass against the background of continued proton pump inhibitor therapy, regardless of smoking, helicobacter infection or use of non-steroidal anti-inflammatory drugs. Initially the patient underwent the laparotomy with perforation suturing and Roux-jejunojejunostomy formation to exclude the bile reflux into the gastric pouch. The result of the first surgery (non-healing ulcer with the development of delayed penetration six months later) is agree with the recent literature about the possible overstatement of the role of biliary reflux in ulcer formation after one anastomosis gastric bypass. The follow-up surgery was performed by the laparoscopic approach in condition of pronounced adhesion process in abdominal cavity and included adhesiolysis, resection of the gastric pouch with the anastomosis and reconstructive Roux-Y-gastric bypass. Clinical and endoscopic evaluation of the result of the reconstructive surgery 10 months after indicates the patient's recovery.