Preschool age is a critical stage for health promotion and prevention of obesity, which is an emerging public health problem in children. The aim of this study was to design and evaluate the effect of a multifaceted intervention based on child-care centers to reduce risk behaviors for obesity among preschool children. A 12-month cluster-randomized community trial was conducted in 16 Mexican Institute of Social Security child-care centers in Mexico City. Children between 2 and 4 years of age enrolled in the selected child-care centers participated in the study. Intervention comprised 12 weekly curriculum sessions for the children, and six family workshops. Changes in children's dietary and physical activity, food availability at home, and maternal feeding styles were determined after 6 and 12 months. Changes within groups among stages, and between groups by stage were analyzed through χ2 test. The intervention showed decrease of home availability for some non-recommended foods and increase in physical activity in the intervention group compared to the usual care group. Improvement in physical activity can be effective in the long term; innovative strategies aimed to modify family dietary risk behaviors are required. Copyright © 2016 Hospital Infantil de México Federico Gómez. Publicado por Masson Doyma México S.A. All rights reserved.