Recent research has shown weight maintenance for obese preadolescent children over 60 and 120 month intervals, while studies on adults consistently show they fail to maintain weight loss. This paper is designed to examine differences in percent overweight changes at 6, 60 and 120 months in obese parents and children from 113 families who participated in randomized controlled outcome studies evaluating family-based behavioral treatment. Analyses showed children had significantly greater changes in percent overweight than their parents at each time point. Chi-Square and Logistic Regression analyses showed children were more likely than their parents at each time point to have percent overweight decreases greater than 20%, with over 20% of the children and less than 1% of the parents showing changes this large. The implications of these results for weight control are discussed. These results suggest there may be differences in the efficacy of treating obesity in children versus adults.