During recent years, obesity has emerged as a major public health problem in the world. It is generally agreed that non-surgical therapies do not solve the problem of morbid obesity (BMI > or =35 kg/m). Therefore, bariatric surgery has been frequently performed for treatments of morbid obesity in American and European countries. In 2008, more than 340,000 bariatric surgical operations (> or =90% laparoscopically) were done, and the typical procedures were laparoscopic Roux-en-Y gastric bypass, adjustable gastric banding and sleeve gastrectomy. Bariatric surgery certainly reduces weight and improves comorbidities and survival in morbidly obese patients. Recently, several bariatric procedures have been also introduced into Japan, and their excellent results in Japanese patients have been already reported.