The Wisconsin Card Sorting Test (WCST) assesses executive and frontal lobe function and can be administered manually or by computer. Despite the widespread application of the 2 versions, the psychometric equivalence of their scores has rarely been evaluated and only a limited set of criteria has been considered. The present experimental study (N = 100 healthy adults) therefore examined the psychometric equivalence of 4 scores (i.e., Total Correct, Percentage of Errors, Perseverative Errors, and Failure-to-Maintain-Set) obtained on the 2 versions of the WCST in terms of 4 key criteria identified within the framework of classical test theory. The results showed considerable differences in variances, small to modest parallel-forms reliability coefficients, and small to modest temporal stability coefficients. Taken together, our results suggest that scores on the manual version and the computer version of the WCST show incomplete psychometric equivalence. (Contains 3 tables.)