Currently, adults older than 50 account for approximately 15% of the total number of acquired immune deficiency syndrome (AIDS) cases. As baby boomers age, the number of older adults infected with the human immunodeficiency virus (HIV) is expected to rise. This expected increase is due, in part, to an increase in the number of individuals newly diagnosed with HIV, and, in part, to improved efficacy of the highly active antiretroviral therapy (HAART) medications used to treat HIV/AIDS. Older individuals who are infected with HIV also are expected to seek treatment for common conditions associated with aging. Thus, a considerable risk for drug interactions between the medications used specifically for HIV treatment and those used for other conditions exists. This article is intended as a guide for gerontological nurses facing these complexities. It includes reviews of the goals of HAART therapy and of the mechanisms of drug interactions, as well as detailed discussions related to the effects of HAART and their potential interactions with medications used to treat conditions commonly found in aging populations.