Background: Roux-en-Y gastric bypass is the most frequently performed bariatric surgery for morbid obesity. Gastrojejunal anastomotic strictures are a relatively frequent postoperative complication. Objective: To evaluate the clinical outcomes and therapeutic response to through-the-scope balloon dilation performed to treat anastomotic strictures after Roux-en-Y gastric bypass surgery. Design: Single-center, retrospective study. Setting: Academic medical center. Patients: Between 1997 and 2005, 801 patients with morbid obesity underwent Roux-en-Y gastric bypass surgery at our institution. Main Outcome Measurements: The development of an anastomotic stricture after Roux-en-Y gastric bypass surgery. The response to through-the-scope balloon dilation after diagnosis. Results: Forty-three of 801 patients (5.4%) developed an anastomotic stricture (26 of 294 open surgeries [8.8%]; 17 of 507 laparoscopic surgeries [3.4%]; P < .001). Strictures were dilated to 15.5 ± 0.4 mm. There were no perforations or clinically significant bleeding after dilation; 93% of the strictures were successfully managed with 1 or 2 endoscopic sessions. Dilation to at least 15 mm did not affect weight loss at 1 year when compared with the group without a stricture (percentage excess weight loss: stricture group, 76%; no stricture group, 74%). Limitations: Single-center, retrospective study. Conclusions: Endoscopic balloon dilation is a safe and effective method for the management of gastrojejunostomy strictures after Roux-en-Y gastric bypass. Dilation to at least 15 mm is safe and decreases the need for further endoscopic dilation.