Moral education is becoming one of the most important topics in school systems today. Schools are fast learning that they must do something to try to teach students good values and even more to teach students how to reason about values. Research studies suggest that athletes are less morally reasoned and less sportsmanlike than their peer groups; that competitive sport places participants in conflict situations where winning is emphasized more than sportsmanship or fairplay; and that a negative relationship exists between moral development and participation in sport. This paper describes a study conducted to analyze the effect of a specific teaching methodology--an intervention based on Piagetian and Kohlbergerian psychology tempered with philosophical theory. The program's goal is to improve cognitive moral development from a hedonistic stage of reasoning to a more autonomous decision making stage. Using qualitative methods, significant behavior changes in student athletes were charted over a 3-year period: fighting decreased, caring about others increased, and classroom behavior and grades improved. The research presented highlights the statistical results, teaching methodology, and classroom environment necessary to bring about both cognitive and behavioral changes in moral development. (LL)