Peptic ulcer in the excluded segment of a gastric bypass has been reported in the literature in only 17 cases. We report a 54-year-old woman with a perforated duodenal ulcer, who had undergone laparoscopic Roux-en-Y gastric bypass surgery for morbid obesity 15 months previously. She was successfully treated by a laparoscopic repair of the perforated duodenal ulcer.