There is a need for efficacious interventions to reduce the prevalence of childhood obesity, and a limited body of research suggests that collaborative community-based programs designed for children and their caregivers may be effective in reducing obesity rates. This paper reports the results of a community-based obesity intervention, South County Food, Fitness and Fun (SCFFF), designed for preadolescent children who are overweight or obese and their caregivers. SCFFF was developed in response to community concerns. Families were referred to the program by their physician and participated in the program at no cost. The 16-week intervention includes weekly group nutrition and physical activity sessions. Analyses determined that 65 out of the 97 children who completed SCFFF provided 2-year follow-up data and had reduced BMI z-scores over 2 years following the intervention. These participants decreased their energy, fat, carbohydrate, saturated fat, and sodium intake and increased core body strength and endurance from baseline to the end of the intervention. SCFFF was effective in reducing relative weight and improving diet and core muscle strength and endurance in children who are overweight or obese.