Recent advances in AIDS treatment have brought renewed optimism for prolonging the lives of those infected with HIV. This article examined beliefs about how new treatments may reduce HIV transmission risk among 298 HIV-negative gay and bisexual men attending a gay pride festival. Results from an anonymous survey showed that men who practiced unprotected anal intercourse as the receptive partner (UAR intercourse) were younger, less well educated, and more likely to believe that it is safe to have UAR intercourse with an HIV-positive man who has an undetectable viral load and that new treatments for HIV relieve their worries about unsafe sex. As HIV treatments continue to advance, new challenges for HIV prevention will likely emerge.