Laparoscopic Y Roux gastric bypass (YRGB) is the most performed bariatric surgery. There are 3 main techniques in the construction of the gastrojejunostomosis (GJA). The size of the GJA and its relation to the reduction of excess weight has been previously debated. The aim of our study was to determine whether the GJA area in YRGB correlates with the loss of excess weight at 1 year postoperatively. Patients who complied 1 year after YRGB underwent an upper gastrointestinal endoscopy. Images of the GJA were obtained and the area of the GJA was calculated. A statistical analysis, adjusting for age and body mass index preoperatively obtained an r of -0474 and P=0.032, demonstrating a significant negative correlation between the GJA area and the percentage of excess weight loss. A statistically significant negative correlation between the GJA area and the percentage of the excess weight loss was shown. The number of patients evaluated should be increased for a higher statistical significance to corroborate whether the stoma size influences the loss of weight in YRGB patients.