The prevalence of obesity has increased in recent decades, and obesity is now one of the leading public health concerns on a worldwide scale. There is accumulating agreement that bariatric surgery is currently the most efficacious and enduring treatment for clinically severe obesity, and as a result, the number of bariatric surgery procedures performed has risen dramatically in recent years. This review will summarize historic and contemporary bariatric surgical techniques, including gastric bypass (open and laparoscopic), laparoscopic adjustable gastric banding, and biliopancreatic diversion (with or without duodenal switch). Data are presented on bariatric surgery outcomes, focusing on weight loss and obesity-related comorbidities. We also review possible complications from surgery. Bariatric surgery patients undergo many dramatic lifestyle changes, and comprehensive presurgical screening conducted by a multidisciplinary team is important to prepare patients for the numerous changes necessary for successful outcome. In addition, comprehensive presurgical screening can aid the treatment team in identifying patients who would benefit from additional services prior to or following surgery. Further research focused on presurgical variables that predict outcome-especially the longer term outcome-of bariatric surgery is needed. At present, approximately 1% of eligible individuals with morbid obesity receive bariatric surgery. In addition, there appears to be inequity in access to weight loss surgery. Given the accumulating evidence that bariatric surgery is efficacious in producing significant and durable weight loss, improving obesity-related comorbidities, and extending survival, the U.S. healthcare system should examine ways to improve access to this treatment for obesity.