In the United States, approximately one in three new human immunodeficiency virus (HIV) infections are transmitted via heterosexual contact. To monitor HIV risk behaviors and HIV prevalence among heterosexuals and other populations, CDC surveys persons in selected metropolitan statistical areas (MSAs), using the National HIV Behavioral Surveillance System (NHBS). This report summarizes data collected from heterosexuals in 24 MSAs with a high prevalence of acquired immunodeficiency syndrome (AIDS) that participated in NHBS during 2006-2007. Of 14,837 heterosexuals aged 18-50 years who were interviewed and tested, 2.0% were HIV infected. HIV prevalence was higher among those with lower socioeconomic status (SES). For example, HIV prevalence was 2.8% among participants with less than a high school education compared with 1.2% among those with more than a high school education, 2.6% among participants who were unemployed compared with 1.0% among those who were employed, and 2.3% among participants with annual household incomes at or below the poverty level compared with 1.0% among those with incomes above the poverty level. This association between HIV prevalence and SES could not be attributed to factors commonly associated with HIV infection risk in heterosexuals, such as using crack cocaine, exchanging sex for things such as money or drugs, or being diagnosed with a sexually transmitted disease (STD). Based on the association observed between HIV prevalence and SES, HIV prevention activities targeted at heterosexuals in urban areas with high AIDS prevalence should be focused on those with lower SES.