The goal of the current study was to investigate how information regarding health threats, specifically the perceptions of Sexually Transmitted Infections (STIs) in different populations, was related to heterosexuals' attitudes toward people of differing sexual orientations. Logically, increasing rates of STIs in heterosexual populations should be the most threatening to heterosexuals. However, common stereotypes about people who are lesbian, gay, or bisexual—especially stereotypes regarding risky sexual activity and promiscuity—may include perceptions that members of these groups are more threatening. This study experimentally manipulated STI rates (shown as either increasing or decreasing) for three groups (heterosexuals, lesbians and gay men, and bisexuals) to assess whether attitudes towards each group would vary as a function of perceived STI rates (i.e., perceived threat). The STI information was presented in a mock brochure as part of project to obtain student feedback for new printed materials for the SDSU Student Health Center (a cover story to deter suspicion from the experimental manipulation). As part of an ostensibly unrelated project, the participants were then asked to fill out a set of surveys regarding their attitudes toward some specific groups on campus (in actuality, they all completed questionnaires regarding attitudes toward heterosexuals, lesbians and gay men, and bisexuals). Participants were 229 SDSU college students recruited from the online psychology participant pool. Results from this study were mixed. Across several dependent measures, attitudes were seen to be more positive towards heterosexuals than sexuality minority groups; additionally, attitudes towards bisexuals were more negative than attitudes towards lesbians and gay men. Contrary to expectations, brochures where STIs were seen as increasing for heterosexuals actually increased positive attitudes towards heterosexuals and decreased attitudes towards sexual minorities. Results and implications from this study are also discussed.