Background: Some patients are thought to regain weight after gastric bypass surgery because of dilation of the gastrojejunal anastomosis (GJA) and/or gastric pouch. Objective: To assess the technical success and safety of an endoscopic procedure, Revision Obesity Surgery Endoscopic (ROSE), using an endoscopic operating system for the placement of tissue anchors to reduce the diameter of the GJA and size of the gastric pouch. Design: Prospective case series. Setting: Brigham and Women's Hospital, Boston, Massachusetts. Patients and Interventions: A total of 20 patients who had regained a mean of 13 kg after gastric bypass, with a dilated pouch and GJA on screening endoscopy, underwent the ROSE procedure. Main Outcome Measurements: Technical success, reduction in size of the GJA and gastric pouch, and early complications. Early weight loss was also assessed. Results: Technical success was achieved in 17 of 20 (85%) patients with an average reduction in stoma diameter of 16 mm (65% reduction) and an average reduction in pouch length of 2.5 cm (36% reduction). The mean weight loss in successful cases was 8.8 kg at 3 months. There were no major complications. Limitations: Single-center case series with a relatively small number of patients and short duration of follow-up, which was inadequate for assessing durable long-term weight loss. Conclusion: The ROSE procedure is technically feasible and appears safe. Data from this series suggest that the ROSE procedure is effective in reducing not only the size of the GJA but also the gastric pouch and may provide an endoscopic alternative for weight regain in gastric bypass patients.