Perforation of a marginal ulcer (MU) is a complication of Roux-en-Y gastric bypass that can be life-threatening. We report a case of a perforated MU that presented 7 months after surgery with several interesting points for discussion. Firstly, the presentation of the ulcer was cryptic with unreliable investigations. Secondly, the ulcer presented again even after anastomotic revision surgery. Finally, the ulcer and the sepsis associated with perforation presented after months of poor nutritional intake with profound hypoalbuminaemia. Perforated MUs causing malnutrition pose clinicians with the difficult decision of which operation to offer; patch repair, revision of the anastomosis or reversal surgery. This case illustrates that primary reversal surgery for a perforated recurrent MU may be the most appropriate surgical management in this clinical situation.