The purpose of this study was to explore how changes in teacher ratings of children's behavior problems from kindergarten to first grade might vary with teachers' styles of managing behavior problems. Familial and socioeconomical variables were controlled because of their potential modulating effects. Subjects were from a community sample of 1,573 boys and girls rated by teachers, mothers and peers (for one part of the sample) on aggressiveness-hyperactivity, anxiety-withdrawal and social skills deficits. Teacher ratings of aggressive-hyperactive behaviors significantly changed from kindergarten to grade one when the teachers had different management styles. Mother and peer ratings, however, did not change. The importance of considering teachers' management styles when assessing behavior problems in school is stressed.