BACKGROUND: Severe obesity has been associated with disordered eating, impaired quality of life (QoL), and decreased physical activity. This study examines changes in these variables 6 months after Roux-en-Y gastric bypass (RYGBP). METHODS: 40 morbidly obese patients were evaluated at baseline and at 6 months after RYGBP on the following measures: Binge Eating Scale, Three Factor Eating Questionnaire, Impact of Weight on Quality of Life-Lite (IWQoL-Lite), and the Baseline Questionnaire of Activity. RESULTS: 6 months after RYGBP, weight loss averaged 26.7%, and scores on measures of disordered eating, weight-related QoL, and physical activity showed statistically significant improvement from baseline. At the time of follow-up, 100% of participants achieved a score on the Binge Eating Scale that indicated no binge eating problems, and weight-related QoL scores approached those obtained by a reference sample of community volunteers. There were also improvements in the level of self-reported physical activity and television watching behavior. CONCLUSIONS: RYGBP resulted in significant improvements in disordered eating, weight-related QoL, and physical activity in addition to weight loss.