The Conners Teacher Rating Scale (CTRS) is a commonly used research and clinical tool for assessing children's behavior in the classroom. The present study introduces the revised CTRS (CTRS-R) which improves on the original CTRS by (1) establishing normative data from a large, representative North American sample, (2) deriving a factor structure using advanced statistical techniques, and (3) updating the item content to reflect current conceptualizations of childhood disorders. Using confirmatory factor analysis, a six-factor structure was found which includes Hyperactivity-Impulsivity, Perfectionism, Inattention/Cognitive Problems, Social Problems, Oppositionality, and Anxious/Shy factors. The reliability of the scale, as measured by test-retest correlations and internal consistency, is generally satisfactory. Using all of the scale factors to discriminate between attention deficit hyperactivity disordered and normal children, 85 percent of children were correctly classified, supporting the validity of the scale and indicating excellent clinical utility. Similarities and differences between the original CTRS factor structure and the CTRS-R factor structure are discussed.