Attention and memory abilities decline with age. Although a similar pattern of attentional and memory decrement has been observed in individuals with Attention Deficit Hyperactivity Disorder (ADHD), these two populations have never been directly compared. The present study examined performance on attention, self-efficacy (SE), and memory tasks by ADHD young adults and non-ADHD younger and older adults. ADHD adults displayed lower attentional SE than both non-ADHD younger and older adults, but performed comparably to older adults on an attention task on which non-ADHD younger adults outperformed both groups. ADHD adults and older adults had lower memory SE than non-AD HD younger adults, but ADHD and non-AD HD younger adults both performed better than older adults on a category cued-recall task. These results suggest that the attentional deficits that characterize both a clinical population and an aging population have similar features. Future directions for research comparing clinical and aging populations on tests of cognitive function are addressed