Obesity remains a major medical disease that often requires surgical intervention in morbidly obese patients. Surgical procedures have evolved and are performed routinely in most major medical centers. Outcomes are often dependent on patient characteristics, type of procedure, and preoperative planning. Risk stratification often depends on screening and optimizing known comorbidities often encountered in this patient population. A thorough understanding of the physiologic changes seen in obese patient and the commonly performed operations will allow the physician to perform optimal treatment strategies.