Bowel obstructions following Roux-en-Y gastric bypass (RYGB) are a significant issue often caused by internal herniation. Controversy continues as to whether mesenteric defect closure is necessary to decrease the incidence of internal hernias after RYGB. Our purpose was to evaluate the effectiveness of closing the mesenteric defect at the jejunojejunostomy in patients who underwent RYGB by examining this potential space at reoperation for any reason.