Bariatric surgery is the most effective and durable treatment of severe obesity. In addition to weight loss, these operations result in significant improvement or resolution of many obesity-related comorbid diseases. There are now numerous studies demonstrating that bariatric surgery decreases all-cause mortality long-term compared with cohorts of patients who did not undergo surgery. Decreases in cancer, diabetes, and cardiovascular-related mortality are major contributors to this overall effect on life expectancy after bariatric surgery.