Surveillance data indicate that HIV incidence among Black women is more than 20 times that among White women and more than 4 times that among Hispanic women. Several studies have examined HIV risk factors by race/ethnicity including high-risk sex, drug use, inconsistent disclosure of same-sex behavior by male partners, and sexually transmitted diseases (STDs). We formed these risk factors into four hypotheses that attempt to explain the higher incidence of HIV infection among Black women. We further conducted a literature review by searching three online databases for studies published between 1985 and 2006 addressing the four hypotheses. Literature suggests that Black women are no more likely to have unprotected sex, have multiple sexual partners, or use drugs than women of other racial/ethnic groups. However, some studies suggest that Black women are more likely to have risky sex partners and STDs. We also found that Black men are less likely to disclose their same-sex behavior to female partners. These four hypotheses are insufficient in explaining the greater burden of HIV among Black women. Future investigations should continue to explore these and other social and behavioral factors such as poverty, health-care access, and receptivity to prevention messages to explain racial/ethnic disparities in HIV incidence.