The purpose of this study was to: (1) examine cognitive performance differences in older and younger adults with and without HIV, and (2) determine if such differences were related to a laboratory measure of instrumental activities of daily living (IADLs). Ninety-eight HIV-positive (69 younger, 29 older) and 103 HIV-negative (84 younger, 19 older) adults were evaluated on a number of cognitive measures. Controlling for a number of confounders, age by HIV status interactions were found on two cognitive measures, indicating poorer cognitive performance for those aging with HIV. Poorer performance on these cognitive measures corresponded with poorer performance on the Timed Instrumental Activities of Daily Living (TIADL) test. These findings suggest that as adults age with HIV, they may be at risk for cognitive declines that would impair their ability to engage in activities important for maintaining independent living.