Early childhood is an important period for interventions to prevent obesity, before poor diet and physical activity behaviors become entrenched and related chronic diseases develop. To date there are still few programs that have been evaluated using experimental study designs that demonstrate impacts on young children’s weight. As a result, it is difficult to know which interventions will truly have an impact. This brief compiles research conducted by the Childhood Obesity Intervention Cost-Effectiveness Study (CHOICES) on interventions that impact young children. The brief provides an overview of the goals of cost-effectiveness analysis, the evidence thus far on the cost-effectiveness of different strategies to prevent obesity in the places where very young children (0- to 5-year-olds) live, learn, and play, and the evidence that is still needed for informed decision-making.