In the last few decades much effort has been devoted to developing prevention programs for eating disorders, as most individuals with these pathologies do not receive treatment and tend to become chronic. The purpose of this study was to evaluate a cognitive dissonance and media literacy intervention aimed at preventing eating disorders in female adolescents. Eighty-eight female students (aged 12-17) from Argentina, participated in a 3-session program. Adolescents completed a baseline, post-intervention and a 6-month follow-up survey. A significant decrease in thin-ideal internalization, body image concerns, influence of advertising, drive for thinness and bulimic attitudes was found at post-intervention. In addition, the number of participants with disturbed eating attitudes and behaviors decreased at post-intervention. Results for body image concerns and drive for thinness were maintained at follow-up.