The association between perceptions about condom use among one's peers, beliefs about new HIV treatments, and HIV sexual risk behavior was examined in a large urban sample ( N = 454) of gay and bisexual men in the Southeast. Results partially confirmed the hypothesis that men who endorsed new HIV treatment beliefs would report lower norms for condom use and higher HIV sexual risk behaviors than men who failed to endorse HIV treatment beliefs but with casual, and not main, partners. Moreover, results confirmed the hypothesis that the association between HIV treatment beliefs and unprotected sex would be partially mediated by peer condom norms. Results suggest social interventions are needed to promote condom norms in the social context of new HIV treatments. (Contains 1 table and 1 figure.)