Bariatric surgery, through its efficacy and improved safety, is emerging as an important and broadly available treatment for people with severe and complex obesity that has not responded adequately to other therapy. Established procedures, such as Roux-en-Y gastric bypass and adjustable gastric banding, account for more than 80% of bariatric surgical procedures globally. Sleeve gastrectomy has emerged as a stand-alone procedure. Truly malabsoptive procedures, such as biliopancreatic diversion and its duodenal switch variant, have a diminishing role as primary procedures, but remain an option for patients who do not respond adequately to less disruptive procedures. The procedures vary considerably in their postoperative morbidity and mortality; pattern and extent of weight loss; nature and severity of long-term complications; and nutritional requirements and risks. There is no perfect procedure--an informed risk and benefit assessment should be made by each patient. Gastroenterologists also need to be familiar with the risks and benefits of current and emerging procedures as they are likely to be increasingly involved in the integrated care of these patients.