While unsafe sex has been reported throughout the HIV epidemic, the underlying assumption has been that most persons do not seek to purposely have unprotected sex. Within the gay community, the term 'barebacking' has emerged to refer to intentional unsafe anal sex. The prevalence of barebacking is evidenced among gay men, particularly those who are HIV-positive, by the number of internet sites devoted to barebacking and the number of men seeking sexual partners through the use of the internet. To gain insight into barebacking, a sample of 112 HIV-positive gay men were recruited from internet sites where men seek to meet each other for sex. The majority of participants (84%) reported engaging in barebacking in the past three months, and 43% of the men reported recent bareback sex with a partner of unknown serostatus. These results indicate the potential for widespread transmission of HIV to uninfected men by the partners they meet on the internet. Analyses revealed that men who reported bareback sex only with HIV-positive partners scored lower in sexual adventurism than those who had bareback sex regardless of partner serostatus. A significant correlation was observed between defining masculinity as sexual prowess and intentional unprotected anal sex. There are serious implications for HIV prevention efforts, in that internet-based education should be a priority in order to reach men who rely on this mechanism to find sexual partners.