We report 10-year treatment outcomes for obese children in 4 randomized treatment studies. At 10 years, 34% decreased percentage overweight by 20% or more, and 30% were not obese. Significant effects were observed when parents and children were targeted and reinforced for weight loss in comparison with nontargeted controls and for children given lifestyle or aerobic exercise in comparison with a calisthenics control. Thirty-four percent of the variance in change in percentage overweight was predicted from sex, baseline percentage overweight, self-monitoring weight, meals eaten at home, and family and friends' support for eating and exercise. Results show long-term changes in children depend on the treatment, and evidence converges on the importance of the family and other sources of support for eating and activity change.