Marginal ulcer (MU) is a known complication after Roux-en-Y gastric bypass (RYGB) that carries significant morbidity. First, we aimed to determine the trends and the rates of readmission, reintervention, and reoperation of 30-day MU. Second, we aim to determine the predictive factors associated with this complication. Patients who had 30-day marginal ulcer (MU) after LRYGB were identified using the 2015-2021 MBSAQIP database. Those who had a 30-day complication other than MU were excluded. Bivariate and logistic regression analyses were performed. Among 213,104 patients undergoing laparoscopic RYGB, 638 (0.3%) showed 30-day MU. This group of patients required endoscopic interventions, readmissions, and reoperations at rates of 88%, 72%, and 9%, respectively. Predictive factors for 30-day MU after RYGB were renal insufficiency, history of DVT, previous cardiac stent, African American race, chronic steroid use, COPD, therapeutic anticoagulation, anastomotic leak test, GERD, and operative time > 120min. Additionally, patients who had 30-day MU showed significantly higher rates of overall complications such as pulmonary, cardiac and renal complications, unplanned ICU admission, blood transfusions, venous thromboembolism (VTE), and non-home discharge (p < 0.05). The MU group showed similar rates of 30-day mortality as those without this complication (0.2% vs 0.1%, p = 0.587). The incidence of 30-day MU following RYGB was 0.3%. Patients with MU required endoscopic interventions, readmissions, and reoperations at rates of 88%, 72%, and 9%, respectively. Some preoperative and intraoperative factors contributed to an increased risk of 30-day MU.