Objective: Bariatric surgery results in significant weight loss and reduces cardiovascular morbidity. However, a large variation in postsurgery weight loss is seen. Physical activity promotes weight loss in nonsurgically treated subjects with obesity. The aim of this study was to investigate the effects of 6 months of supervised physical training following Roux-en-Y gastric bypass surgery (RYGB) on body weight and cardiovascular risk markers. Methods: Sixty participants eligible for RYGB were included. Six months post surgery, the participants were randomly assigned to either twice-weekly supervised physical training sessions in a fitness center (INT) or a control group (CON) for 26 weeks. Before surgery and 6, 12, and 24 months after surgery, the participants underwent an examination program that included anthropometric measurements, blood pressure, heart rate, blood samples, and an abdominal computed tomography scan. Results: RYGB significantly reduced body weight and improved cardiovascular risk markers (all P<0.01). The supervised physical training intervention resulted in a 4.2-kg (CI: -0.2 to -8.3 kg) lower body weight in INT compared with CON at the study end (P=0.042). The high-density lipoprotein concentration was significantly higher in INT than in CON at the termination of the intervention, but this was not maintained at the 24-months examination. Conclusions: Physical training following RYGB improves weight loss and cardiovascular health.