As of December 2001, a cumulative total of 816,149 cases of acquired immunodeficiency syndrome (AIDS) had been reported to CDC (1). One of CDC's national human immunodeficiency virus (HIV)--prevention goals for 2005 (Goal 2) is to increase the proportion of HIV-infected persons in the United States who know they are infected from an estimated 70% to 95% (2). A goal of the new CDC initiative, Advancing HIV Prevention: New Strategies for a Changing Epidemic, is to ensure that every HIV-infected person has the opportunity to be tested and has access to state-of-the-art medical care and prevention services needed to prevent HIV transmission (3). To characterize the prevalence of HIV-antibody testing among U.S. adults, CDC analyzed data from the 2001 Behavioral Risk Factor Surveillance System (BRFSS). The findings document variability in HIV testing prevalence by area and by sex within areas, underscoring the ongoing need to promote voluntary HIV counseling and testing that will provide persons with early knowledge of their HIV status and offer them access to appropriate counseling and treatment.