BACKGROUND Anastomotic stenosis presents as one of the most common late complications in the postoperative period after bariatric surgery. It is often diagnosed by upper gastrointestinal series (UGIS) and/or upper endoscopy (UE). The aim of this study was to determine whether a correlation exists between the Gastrografin UGIS and UE findings in the determination of gastrojejunal anastomotic strictures after Roux-en-Y gastric bypass (RYGB). METHODS Between July 2001 and October 2003, all medical records of patients who underwent RYGB at our institution were retrospectively reviewed. The medical records of patients who underwent UE because of symptoms suggestive of gastric outlet obstruction and those of patients who were initially evaluated by Gastrografin UGIS before UE were evaluated further. RESULTS Of 535 morbidly obese patients who underwent RYGB, 52 (9.7%) had UE and were included in this study. The mean number of UEs performed per patient was 2.67. Of these 52 patients, 30 underwent Gastrografin UGIS before UE. The mean diameter of the anastomosis on the first UE was 5.97 mm and on Gastrografin UGIS was 6.83 mm. A good correlation was found between the Gastrografin UGIS and UE findings using Pearson's correlation coefficient (0.44, P = .02) and single linear regression analysis using the endoscopic diameter as the outcome and radiographic findings as the predictor (beta = 0.27, P = .025, 95% confidence interval 0.30-0.49). CONCLUSIONS In our study, the Gastrografin UGIS findings correlated positively with the endoscopic gastrojejunal anastomosis findings in patients with anastomotic stricture who had undergone RYGB.