The Wisconsin Card Sorting Test (WCST) has frequently been used to assess executive functions in children with attention deficit hyperactivity disorder (ADHD). We first compared the performance of 15 children with ADHD to 15 children of a control group (age range 6 to 11) on the WCST and then examined the relationship among working memory, inhibition, age, IQ, and scores from this test. When age and IQ were included as covariates, children with and without ADHD did not differ on the perseverative errors (PE) score, but the ADHD group made significantly more failure to maintain set errors (FTMS). Partial correlations revealed that working memory was significantly correlated with PE but was fully mediated by age and IQ. Age and IQ had no effect on the significant correlation between inhibition and FTMS. Clinicians are encouraged to interpret the results of this test with caution when including it in an assessment for ADHD. (Contains 4 tables.)