Objective: Preventing weight gain in adults and excessive weight gain in children is a high priority. We evaluated the ability of a family-based program aimed at increasing steps and cereal consumption (for breakfast and snacks) to reduce weight gain in children and adults. Research Methods and Procedures: Families (n = 105) with at least one 8- to 12-year-old child who was at-risk-for-overweight or overweight (designated as the target child) were recruited for the study. Eighty-two families were randomly assigned to receive the family-based intervention and 23 families to the control condition. The 13-week intervention consisted of specific increases in daily steps (an additional 2000 steps/d) and consumption of 2 servings/d of ready-to-eat cereal. Results: The intervention was successful in increasing walking (steps) and cereal consumption. The intervention had positive, significant effects on percentage BMI-for-age and percentage body fat for target children and weight, BMI, and percentage body fat for parents. On further analysis, the positive effects of the intervention were seen largely in target girls and moms, rather than in target boys and dads. Discussion: This family-based weight gain prevention pro gram based on small changes holds promise for reducing excessive weight gain in families and especially in growing overweight children. Copyright © 2006 NAASO.