From the abstract: In the past 20 years, obesity rates among U.S. children have skyrocketed. In fact, 15.4% of 2- to 4-year-olds in North Carolina, where this study takes place, are obese, making it the 5th worst obesity rate in the nation. Research indicates that young children in preschool settings largely engage in sedentary activities, demonstrating the need for programs that encourage physical activity. Starting physical activity early helps children set patterns for lifelong learning and participation. In this article we describe the development and evaluation of a program of physical activities, Be Active Kids, designed to increase the level of physical activity of children birth to age 5 in child care settings in North Carolina. Using a single case study, multiple baseline design, we introduced the intervention in 6 classrooms in 3 child care centers. Teachers received a standardized training, and children in each classroom were observed for their level of physical activity during the baseline and treatment phases. Results demonstrated that teacher training and implementation of physical activities increased light and moderate/vigorous physical activity and was particularly effective when activities were teacher directed. Practice or Policy: This study provides evidence that a program of physical activity can help even the youngest children to be more physically active.