Individuals 50 years of age or older continue to account for at least 10% of AIDS cases reported to the Centers for Disease Control and Prevention in recent years. Little research is devoted to addressing the specific issues affecting diagnosis, treatment, and prevention of AIDS in older Americans. Survival rates among elderly individuals infected with human immunodeficiency virus (HIV) are consistently decreased in comparison with those for younger patients. Elderly individuals also are less likely to use a condom during sexual intercourse or to participate in routine HIV testing. This article reviews the current literature concerning the changing epidemiology of AIDS among older Americans. The article also addresses AIDS-related morbidity and mortality, treatment issues, and HIV-prevention behaviors among the elderly. Enhanced clinician awareness of HIV in the elderly, along with further research concerning HIV treatment and prevention, is necessary to improve survival and outcome for those patients.