An epidemiological survey of the frequency and severity of aggressive and disruptive behaviors found in elementary school classrooms was conducted. One hundred and forty regular education and special education teachers from the area surrounding Tucson, Arizona rated 12 classroom behavior problems for 3,135 male and female, Anglo and Hispanic students. Teachers' ratings were found to differ according to student ethnicity and gender. Anglos were rated as displaying more severe behavior problems in the classroom than Hispanics and males were rated as displaying more severe behavior problems than females. Consistent with these findings, different factor structures were identified for teacher ratings of male and female, and Anglo and Hispanic students. Implications of these findings for educators, administrators, and school psychologists are discussed.