**1. Introduction**

The global prevalence of obesity has tripled since 1975 [1]. Obesity is managed according to the severity and associated comorbid conditions. Bariatric surgery is recommended for class II obesity with associated comorbidities and class III obesity. It confers the most effective and durable weight loss. The number of bariatric procedures in the United States has significantly increased in the last decade [2].

The primary outcome of bariatric surgery is weight loss; however, it also improves obesity-related comorbidities and overall survival.

Bariatric surgery has progressed significantly since its origin in 1954. In contemporary practice, Roux-en-Y gastric bypass surgery (RYGB), sleeve gastrectomy (SG) and adjustable gastric band (AGB) are the most performed procedures. This chapter will focus on the outcomes of these three surgical techniques.
