Anastomotic stricture is a frequent complication after Roux-en-Y gastric bypass (GBP). We evaluated the frequency of anastomotic stricture following laparoscopic GBP using a 21 mm. vs. a 25 mm circular stapler for construction of the gastrojejunostomy and the safety and efficacy of endoscopic balloon dilation in the management of anastomotic stricture. We reviewed data on 29 patients in whom anastomotic strictures developed after laparoscopic GBP. All strictures were managed with endoscopic balloon dilation using an 18 mm balloon catheter under fluoroscopic guidance. Main outcome measures were the number of anastomotic strictures in patients in whom the 21 mm (vs. 25 mm) circular stapler was used to create the gastrojejunostomy, time interval between the primary operation and symptoms, complications of endoscopic balloon dilation, the number of patients with resolution of obstructive symptoms, and body weight loss. There were 28 females with a mean age of 39 years and a mean body mass index of 48 kg/m(2). Anastomotic stricture occurred significantly more frequently with the use of the 21 mm compared to the 25 mm circular stapler (26.8% vs. 8.8%, respectively; P<0.01). The median time interval between the primary operation and presentation of stricture was 46 days. After the initial dilation, recurrent stricture developed in 5 (17.2%) of 29 patients. These five patients underwent a second endoscopic dilation, and only one of these five patients required a third endoscopic dilation. None of the 29 patients required more than three endoscopic dilations. The mean percentage of excess body weight loss at 1 year for patients in whom the 21 mm circular stapler was used for creation of the gastrojejunostomy was similar to that for patients in whom the 25 mm circular stapler was used (68.2% vs. 70.2%, P=0.8). In this series the rate of anastomotic stricture significantly decreased with the use of the 25 mm circular stapler for construction of the gastrojejunostomy without compromising weight loss. Endoscopic balloon dilation is a safe and effective option in the management of anastomotic stricture following laparoscopic GBP.