This study examined the psychometric properties of the Children's Yale?Brown Obsessive?Compulsive Scale (CY?BOCS; Scahill et al., 1997). Participants were 82 children and adolescents diagnosed with obsessive?compulsive disorder (OCD). Confirmatory factor analyses of 2 previously found models (Obsessions and Compulsions; Disturbance and Severity) yielded poor fit indexes. Exploratory factor analysis supported a model of severity and disturbance with slightly different item content than found by McKay et al. (2003). The internal consistency of the factors was acceptable, and the convergent and divergent validity was supported vis-a-vis correlations with clinician ratings of impairment, self-report measures of depression and anxiety, and parent ratings of Tourette's disorder (TD) symptoms. These findings suggest that the CY?BOCS Total Score may represent an inaccurate assessment of symptom severity and supports the use of the revised Severity and Disturbance factors in assessing illness severity.