The Reynolds Intellectual Assessment Scales (RIAS) is a recently developed, individually administered psychometric instrument designed to measure general cognitive ability, as well as verbal (crystallized) intelligence, nonverbal (fluid) intelligence, and memory. Test reviewers have recommended the use of the RIAS despite the fact that, although the RIAS has been in circulation for more than four years, there is a paucity of independent research published about its psychometric properties. The purpose of the current study was to examine the factor structure of the RIAS across three samples of school-age children: the RIAS norming sample; the data reported by Nelson, Canivez, Lindstrom, and Hatt; and a new, independent sample of students referred for special education services. Using confirmatory factor analytic techniques, this study found that a two-factor model, positing verbal and nonverbal factors, fit all three data sets better than a one-factor model. Furthermore, the two-factor model demonstrated partial measurement invariance across the three samples, although the verbal factor showed much stronger invariance, construct reliability, and overall interpretability than did the nonverbal factor. Implications of this study for practitioners are discussed. © 2009 Wiley Periodicals, Inc.