Single-anastomosis duodeno-ileal bypass with sleeve (SADI-S) was first described in 2007 as a simplified version of the biliopancreatic diversion with duodenal switch. SADI-S has achieved satisfactory short and long-term results for the treatment of both morbid obesity and its metabolic comorbidities. SADI-S is a safe, reproducible and effective bariatric procedure that offers excellent weight loss and metabolic outcomes as a malabsorptive technique. In this chapter, the procedure is described step by step, including representative intraoperative images.