The Roux-en-Y gastric bypass (RYGB) is a worldwide-performed procedure as primary surgery, and as conversional procedure after complications and/or failure of other bariatric procedures. RYGB can be performed as revisional surgery after adjustable gastric banding, vertical banded gastroplasty, sleeve gastrectomy and one anastomosis gastric bypass. Each of these revisional procedures may be technically challenging, and accurate preoperative work-up and operative planning is required. If correctly performed, RYGB as revisional procedure is associated with satisfying outcomes and is indicated in the treatment of insufficient weight loss and postoperative complications of a primary bariatric procedure - such as chronic leak or gastroesophageal reflux after sleeve gastrectomy. The present article analyzes the most important indications, technical points and tips and tricks to safely perform RYGB as a secondary procedure.