Young adults with attention deficit-hyperactivity disorder (ADHD; N = 105) were compared with a control group (N = 64) on 14 measures of executive function and olfactory identification using a 2 (group) X 2 (sex) design. The ADHD group performed significantly worse on 11 measures. No Group X Sex interaction was found on any measures. No differences were found in the ADHD group as a function of ADHD subtype or comorbid oppositional defiant disorder. Comorbid depression influenced the results of only 1 test (Digit Symbol). After IQ was controlled for, some group differences in verbal working memory, attention, and odor identification were no longer significant, whereas those in inhibition, interference control, nonverbal working memory, and other facets of attention remained so. Executive function deficits found in childhood ADHD exist in young adults with ADHD and are largely not influenced by comorbidity but may be partly a function of low intelligence.