Abstract : Duodenal ulcer perforation in patients undergoing gastric bypass surgery is a rare late complication, occurring in less than 1% of cases. It carries a high mortality risk, particularly in cases of delayed diagnosis. The challenge lies in an unspecific clinical presentation and laboratory findings, as well as a CT scan not very helpful in almost half of cases. These features may lead to the consideration of other differential diagnoses, such as pancreatitis or cholecystitis. A multidisciplinary approach in collaboration with digestive surgeons is essential to enable rapid exploratory laparoscopy in presence of diagnostic uncertainty, and appropriate therapeutic management.