OBJECTIVE: To determine if method of weight loss (surgery; non-surgery) is associated with current levels of psychosocial functioning or current weight maintenance behaviors in individuals who have lost large amounts of weight. DESIGN: Subjects were 67 cases and 67 controls selected from the National Weight Control Registry, a longitudinal study of individuals successful at long-term maintenance of weight loss. Cases had initially lost weight through bariatric surgery while controls had lost weight through non-surgical means. The current psychosocial functioning and weight maintenance behaviors of cases and controls were assessed and compared. RESULTS: Cases and controls were matched on gender, current weight and total weight loss. Surgical cases reported significantly higher fat intake and lower physical activity levels. There were no differences in cases' and controls' reports of the impact of weight loss on other areas of their lives, neither were there differences on measures of depression or binge-eating. CONCLUSIONS: Reported improvement in psychosocial functioning did not depend upon how weight was initially lost, but cases and controls appear to be using very different behaviors to maintain their weight losses.