New cases of HIV/AIDS are disproportionately diagnosed among men who identify as lesbian, gay, and bisexual and Black. Reasons for this disparity may be related to differences in knowledge of how HIV/AIDS is transmitted and differences in willingness to engage in risky sexual behaviors. In this study, we examined whether differences in knowledge of HIV/AIDS transmission and engagement in risky sexual behaviors differed among men and women; lesbian, gay, and bisexual and heterosexual people; and White and Black people. Findings indicate knowledge of HIV/AIDS transmission was not related to sexual orientation or gender; however, White participants had higher scores on a measure of knowledge of HIV/AIDS transmission than Black participants. While neither gender nor race seemed to be related to differences in engaging in risky sexual behavior, differences in what types of risky sexual behavior people participated in existed based on sexual orientation. Implications for prevention efforts are addressed.