Despite extensive use of the Children's Yale Brown Obsessive Compulsive Scale (CYBOCS; Scahill et al., 1997), the lack of normative data impedes interpretation of individual CYBOCS scores. Consequently, psychometrics on CYBOCS severity scores from 815 treatment-seeking youth with obsessive-compulsive disorder (OCD) are presented, across age and sex, so that normative comparisons of obsessive, compulsive, and combined obsessive-compulsive severity could be calculated. Our findings suggest no evidence for marked age or sex differences. Further, obsessive-compulsive symptom severity scores (measured via the CYBOCS) appear consistent with global OCD syndrome severity (measured via the Clinician Global Impression-Severity scale [CGI-S; Guy, 1976]; r = .58). This study contributes the 1st empirically based guidelines for interpreting obsessive-compulsive symptom severity scores. After a diagnosis of OCD is determined, the CYBOCS can be used to determine severity of illness (however, categories of severity proposed by this article should not be used in the screening of OCD symptoms). Findings can facilitate clinicians' and investigators' ability to draw comparisons across obsessive-compulsive severity scores.