Chronic marginal ulcers are a rare complication after gastric bypass. A large gastric pouch may be responsible for elevated acid production. We present the case of a 43 year old female with a weight of 347 lbs a BMI of 54.1 who underwent an open gastric bypass in 2003. Four months after surgery she developed a marginal ulcer and was given high doses of proton pump inhibitors. Twelve months after surgery she experienced a recurrence. Twenty-four months after surgery, it was decided to perform a reversal of the gastric bypass. The retro-gastric transmesocolic alimentary limb was dissected, and the gastro-jejunostomy was identified. We opened the anastomosis and identified a large marginal ulcer penetrating the liver,covered with fibrin. The gastric pouch was very large. At this point we decided against performing a Sleeve Gastrectomy or Biliopancreatic Diversion and instead, chose to proceed with a gastro-gastrostomy between the gastric remnant and the gastric pouch.This was done by firing two loads of 45mm staples. The patient was discharged 12 days after surgery and was able to tolerate a puree diet. Laparoscopic gastro-gastrostomy is a feasible treatment of chronic marginal ulcers after gastric bypass.