The study evaluated the effectiveness of positive social teacher approval contingent upon prosocial behavior by two abused preschoolers toward peers with similar background. Using a single subject ABAB research design, results supported the relationship between positive social teacher approval and increased positive student behavior, decreased negative behavior and increased prosocial behavior of peers toward Ss. Findings demonstrated the effectiveness of systematically applied behavioral principles in improving the social interaction for maltreated students and improving the quality and quantity of social interaction for the classroom as a whole. (CL)