Background: Over the last 3 decades, US obesity rates have increased dramatically as more children and more adults become obese. This study explores an innovative program, Active Generations, an intergenerational nutrition education and activity program implemented in out-of-school environments (after school and summer camps). It utilizes older adult volunteers to implement a version of the evidence-based childhood obesity prevention program, Coordinated Approach to Child Health, in 8 US cities. Methods: Approximately 760 children in third- to fifth-grade participated in Active Generations, a 10-lesson, intergenerational, childhood obesity prevention program. Children completed an age-appropriate survey instrument, the Active Generations survey (AGS). The AGS is a valid and reliable, self-administered, self-report, paper-and-pencil survey designed to assess knowledge, attitudes, and behaviors. It was administered by trained volunteers on the first day and last day of the program. Constructs assessed included physical activity, nutrition, and media use. Results: Students significantly increased their reported fruit and vegetable consumption post-program. For example, the percentage of students reporting eating 3 or more servings of vegetables per day was 16% greater post-program. Students were more likely to report reading food labels and greater confidence that they could participate in physical activity. They also significantly decreased their daily screen time. Conclusions: Active Generations is a promising childhood obesity prevention program. (Contains 1 table.)