Laparoscopic Roux-en-Y Gastric Bypass (RYGB) is a commonly used method in bariatric surgery that leads to sufficient long-term weight loss and consequently to improvement or resolution of obesity-associated diseases. The nadir weight is commonly reached between six months and two years after surgery. Despite this initially good weight loss, weight regain is observed in up to 20% of the patients. Besides intensive dietological evaluation, bariatric re-operation can be an option in these cases. Before the surgical reintervention, an intensive evaluation of the esophagus, pouch, anastomosis, and adjacent small bowel using upper GI-endoscopy and radiological examinations (X-ray and/or 3D-CT volumetry) is mandatory. In patients with a dilated pouch, pouch-resizing with a MiniMIZER® Gastric Ring (Bariatric Solutions GmbH, Stein am Rhein, Switzerland) could be an option to reestablish restriction in the long term. Currently, there is no gold standard for the choice of the weight regain procedure or for the technique used in the procedure itself. This article focuses on the standardized procedure of pouch resizing with implantation of a MiniMIZER® Gastric Ring for the surgical therapy of weight regain due to pouch dilatation and/or dilatation of the gastrojejunostomy and the adjacent small bowel (usually approximately the first 20cm), resulting in a huge neo-stomach after RYGB, as performed at the Medical University of Vienna. Further, indications for revisional surgery for weight regain, mandatory examinations, and recommended conservative therapy options prior to surgery will be described. Next, the fast-track concept and its advantages are explained. Lastly, the surgical procedure, including positioning of the patient, placement of trocars, the intraoperative process, and special advice, is presented. Exact planning of the procedure and postoperative follow-up are indispensable for a further long-term success after weight regain surgery. In conclusion, pouch-resizing and implantation of the MiniMIZER® Gastric Ring represent a practical and effective solution in patients with dilated pouch/anastomosis/adjacent small bowel with weight regain after RYGB, if conservative therapy, including dietitian counseling and new drugs (e.g., Semaglutide), has failed.