Background: Yale University's Bright Bodies Program consists on a lifestyle intervention, in areas such as nutrition and exercise, while focusing on behavior modification and family support. Aim: To evaluate the impact of the Program in Chilean children and adolescents with obesity who participated in the Program during 8 months. Material and Methods: The weight management Program was carried out during 8 months and consisted in weekly sessions directed by dietitians or psychologists and exercise sessions twice per week in charge of physical education teachers. The family component was based on sessions for parents or caregivers to achieve the same goals of children activities. Results: Twenty eight obese children aged 9.5 +/- 2 years completed the eight months of intervention. There was a significant 5% reduction of body mass index (BMI), a 15% reduction of BMI z score and a 2.9% reduction of waist circumference. Bioelectrical impedance showed a 9% reduction of percentage body fat and a 7% increase in lean body mass. Blood pressure, blood glucose, total and LDL cholesterol and triglycerides decreased significantly, without changes in HOMA-IR. The frequency of metabolic syndrome decreased from 36% at baseline to 18% at the end of the intervention. A 43% reduction in caloric intake and an improvement in physical condition was also observed. Conclusions: The Bright Bodies Program produced significant and positive changes on anthropometric and metabolic parameters in this group of children.