Gastric bypass is a technique that helps combat obesity, is a surgery that is practiced for more than 40 years, and specialists have been improving since that day. Gastric bypass surgery is a laparoscopically, meaning only makes a small incision by which a camera will be introduced to thus be able to perform the operation. Gastric bypass is famous and very accomplished thanks to its great effectiveness, weight loss is due to the reduction of the stomach and to the reorganizamiento of the small intestine, stomach joining the portion of the intestine that is not responsible for absorption. By reducing the patient eats less, this is a way of losing weight, and also thanks to the rearrangement, also decreases the absorption of calories, sugars, and other substances that cause obesity. Gastric bypass surgery is recommended for many patients who suffer from obesity, because its results are guaranteed, this insured that after have been subjected to a gastric bypass, is very difficult or virtually impossible to regain lost weight. In Monterrey the gastric bypass has become a solution for the majority of patients suffering from obesity, the characteristics of a patient’s gastric bypass is that has suffered from obesity for more than 5 years in a row, with a very high body mass index. This operation is not completed to people who smoke or have history of alcohol abuse.