This practicum set up a classroom-based model for peer mediation in grades 3 and 4. During the project's implementation, the school psychologist delivered, individually to each of 6 different third and fourth-grade classrooms, 8 weeks of classroom instruction on conflict resolution. When all 6 classes were familiar with conflict resolution techniques, the classroom teachers, with the aid of the school psychologist, chose 30 students to take part in more intensive training and to serve as peer mediators, or, as this model referred to them, Peacebusters. All third- and fourth-grade students agreed to comply with the peer mediation rules and to have their conflicts resolved by Peacebusters during unstructured school time. Analysis of the evaluation data showed that all students who were part of the intervention became familiar with conflict resolution methods and the classrooms became more peaceful environments in which the children could learn, cooperate, and get along with one another. As a result of intervention, a peer mediation manual was developed for future use in grades 1 through 4. (Nine appendices include the student peace journal, peer mediation report and follow up questionnaire, and the Peacebusters manual. Contains 18 references.) (AA)