Disruptive behavior disorders (e.g., attention-deficit/hyperactivity disorder and oppositional defiant disorder) are increasingly being diagnosed in preschool children. However, the assessment and differential diagnosis of these disorders presents several challenges to clinicians. For example, most rating scales used to help diagnose such problems were developed using school age children. Thus, the psychometric properties of many commonly used assessment tools have yet to be investigated with a preschool population. The purpose of this study is to investigate the psychometric properties of the Disruptive Behavior Disorders Rating Scale (DBDRS) and the School Situations Questionnaire (SSQ) when used with a community sample of at-risk preschool children. Results indicate that both measures have adequate psychometric properties for use with preschoolers. Additionally, as with school-age populations, a three-factor solution, with factors reflecting inattentive, hyperactive-impulsive, and oppositional defiant behaviors, was the best fit for the DBDRS data. Implications for clinicians are discussed, as are limitations and suggestions for future research. (Contains 10 tables.)