Biliopancreatic diversion is a malabsorptive technique of bariatric surgery that has gained wide acceptance in the Western world. It is performed in one of two ways: In its classic form it consists of partial gastrectomy with a Roux-en-Y gastroenterostomy; in its duodenal switch form a vertical sleeve gastrectomy is combined with a duodenoenterostomy. Both techniques realize diversion of biliopancreatic juice, thereby creating a mild form of malabsorption. Weight loss has been approximately 70% of initial excess weight, exceeding that obtained with most other bariatric procedures. Iron, calcium, and vitamin deficiencies may occur, especially with classic biliopancreatic diversion, and must be prevented with adequate supplements during vigorous follow-up. Weight loss is followed by a substantial reduction in the co-morbidities that are present in many morbidly obese patients. Biliopancreatic diversion should be included in each obesity clinic program and be proposed for morbidly obese patients who are having difficulty with the prospect of continuous restraint of food intake or problems due to failed gastric restrictive interventions. The postoperative results in such patients have been good and have substantially improved quality of life and self-esteem in this category of morbidly obese patients.