 The only effective treatment for patients with morbid obesity is bariatric surgery. Sudden weight loss following bariatric operations for morbid obesity, such as Roux-en-Y gastric bypass RYGBP can result in a concurrent decrease in lean body mass. However the long-time results weight reduction, elimination co-morbidities are depending on the post operative treatment. Aerobic physical exercising APE is well accepted in conservative treatment of obesity as well as of diabetes mellitus type 2 DM. The aim of this study was to assess the efficiency of APE on weight loss, body composition and co-morbidities in patients after laparoscopic Roux-en-Y Gastric bypass RYGBP. 