Cuidando El Corazon (CEC; Taking Care of Your Heart) was designed to assess the effectiveness of a culturally adapted weight-reduction and exercise program for achieving long-term weight loss in Mexican Americans. CEC used a family-oriented approach to achieve lifestyle change in behavior. Participants were assigned to 1) a booklet-only comparison group that received a manual including behavior change, nutrition, and exercise information and traditional recipes modified in fat content; 2) an individual group that received the same manual and attended year-long classes; or 3) a family group that received a manual and attended classes that emphasized techniques for making changes in the family's eating and exercising habits. The family and individual groups had significantly greater weight losses than the information-only group. Weight loss was greatest in the family-involvement group and least in the information-only comparison group.