Context: Rates of heterosexually transmitted HIV infection among African Americans in the southeastern United States greatly exceed those for whites. Objective: Determine risk factors for heterosexually transmitted HIV infection among African Americans. Methods: Population-based case-control study of black men and women, aged 18-61 years, reported to the North Carolina state health department with a recent diagnosis of heterosexually transmitted HIV infection and age- and gender-matched controls randomly selected from the state driver's license file. A lower-risk stratum of respondents was created to identify transmission risks among people who denied high-risk behaviors. Results: Most case subjects reported annual household income <$16,000, history of sexually transmitted diseases, and high-risk behaviors, including crack cocaine use and sex partners who injected drugs or used crack cocaine. However, 27% of case subjects (and 69% of control subjects) denied high-risk sexual partners or behavior. Risk factors for HIV infection in this subset of participants were less than high school education (adjusted odds ratio [OR] 5.0; 95% CI: 2.2, 11.1), recent concern about having enough food for themselves or their family (OR 3.7; 1.5, 8.9), and having a sexual partner who was not monogamous during the relationship with the respondent (OR 2.9; 1.3, 6.4). Conclusion: Although most heterosexually transmitted HIV infection among African Americans in the South is associated with established high-risk characteristics, poverty may be an underlying determinant of these behaviors and a contributor to infection risk even in people who do not have high-risk behaviors. Copyright © 2006 by Lippincott Williams & Wilkins.