INTRODUCTION: Anastomotic stricture is a frequent complication after laparoscopic and open 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 anastomosis and the safety and efficacy of endoscopic hydrostatic dilation in the treatment of anastomotic stricture. METHODS: We reviewed data on anastomotic stricture in our first 150 consecutive laparoscopic GBP patients. Anastomotic stricture was defined as patients presenting with symptom of vomiting and the inability to pass a 9.8 mm diameter endoscope through the gastrojejunostomy anastomosis. Endoscopic dilation was performed with an 18 mm balloon catheter under fluoroscopy. Main outcome measures of the study were symptoms at presentation, time interval between the primary operation and symptoms, complications, and body weight loss. RESULTS: Twenty-five (16.7%) of the 150 patients developed postoperative anastomotic stricture. There were 24 females with a mean age of 39 years. All patients presented with a primary symptom of nausea and vomiting. Anastomotic stricture occurred in 19 (26.8%) of 71 patients who underwent laparoscopic GBP using a 21 mm circular stapler and 6 (7.6%) of 79 patients who underwent laparoscopic GBP using a 25 mm circular stapler. The mean time interval between the primary operation and presentation of stricture was 2.5 months. Endoscopic dilation was performed under general anesthesia in 72% of patients and intravenous sedation in 28%. The mean stoma size observed at endoscopy was 3.9 mm. All procedures were performed on an outpatient basis and there was no postoperative complication. Five (20%) of 25 patients required a second dilation and 1 (4%) of 25 patients required a third dilation. The mean percentage of excess body weight loss (EBWL) for patients who developed stricture at 1 year was 69.8% compared to 68.7% for patients who did not developed stricture (p = 0.7) and the mean percentage of EBWL at 1 year for patients who had the 21 mm circular stapler for creation of the gastrojejunostomy was 68.2% compared to 70.2% for patients who had the 25 mm circular stapler (p = 0.8). CONCLUSION: The rate of anastomotic stricture significantly decreased with the use of the 25 mm circular stapler for construction of the gastrojejunostomy anastomosis without compromising weight loss. Hydrostatic balloon dilation is a safe and effective option in the management of anastomotic stricture following laparoscopic gastric bypass.