Naming, or word-finding ability, is typically assessed using measures that require a patient to name a pictured object. Words used less frequently tend to be more difficult to find when speaking; thus word frequency can be used as a measure of item difficulty on such tests. However, frequency data for words on naming measures has either not been used in the creation of these tests or has been derived from data on how frequently words have been used in written materials. The present study determined how frequently words on the Boston Naming Test (BNT), the Neuropsychological Assessment Battery (NAB) naming subtest, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) naming subtest, and auditory naming measures developed by Hamberger and Seidel (2003, Journal of the International Neuropsychological Society, 9, 479) and Brandt et al. (2010, The Clinical Neuropsychologist, 24, 1326) are used in spoken language. Items on the auditory naming measures had the highest mean frequency, and the BNT items 30-60 had the lowest mean frequency. Furthermore, item frequency on the full BNT, NAB naming forms 1 and 2, and RBANS forms A correlated with item number, indicating items increase in difficulty on these tests, with trends in the same direction found for RBANS form B and Hamberger and Seidel's auditory naming measure. Finally, differences in mean word frequency between tests underscore how interpretation of change in naming ability based on different measures should be made with caution.