Laparoscopic Roux-en-Y gastric bypass (LRYGB) is the gold standard in bariatric surgery. A long-term complication can be marginal ulceration (MU) at the gastrojejunostomy. The mechanism of development is unclear and symptoms vary. Management and prevention is a continuous subject of debate. The aim was to assess the incidence, mechanism, symptoms, and management of MU after LRYGB by means of a systematic review. Forty-one studies with a total of 16,987 patients were included, 787 (4.6%) developed MU. The incidence of MU varied between 0.6 and 25%. The position and size of the pouch, smoking, and nonsteroidal inflammatory drugs usage are associated with the formation of MU. In most cases, MU is adequately treated with proton pump inhibitors, sometimes reoperation is required. Laparoscopic approach is safe and effective.