Mini Gastric Bypass surgery is a weight loss surgery that is primarily a malabsorptive procedure in which a long narrow gastric tube is created and joined directly to the mid portion of the small intestine. It differs from the classical RYGB in the size of the gastric pouch which is considerably larger and the diameter of the anastomosis between the pouch and the intestine which is also wider.

As a result, the patient is able to eat larger portions of food than that possible after a RYGB. The main mechanism by which this procedure works is malabsorption due to delay in the mixing of food and digestive enzymes. It also results in effective excess weight loss of upto 80% with remission of comorbid diseases.