Objectives: To demonstrate that high IQ adults diagnosed with ADHD suffer from executive function (EF) impairments that: a) can be identified with a combination of standardized measures and self-report data; and b) occur more commonly in this group than in the general population. Method: 157 ADHD adults with IQ greater than or equal to 120 were assessed with 8 normed measures of EF-3 index scores from standardized tests of memory and cognitive abilities, and 5 subscales of a normed self-report measure of EF impairments in daily life. Results: 73% of subjects were significantly impaired on greater than or equal to 5 of these 8 EF markers. On all 8 measures, incidence of these impairments was significantly greater than in the general population. Conclusion: High IQ adults with ADHD tend to suffer EF impairments that can be assessed with these measures; incidence of such impairments in this group is significantly higher than in the general population. (Contains 4 figures.)