In this study, we examined how non-infectiousness due to antiretroviral therapy has affected HIV-positive gay men’s experience of serostatus disclosure to casual sex partners. Interviews were conducted with 15 seropositive gay men living in Ireland. Using grounded theory, three constructions of non-disclosure were proposed—as self-protection, as a morally permissible act, and as a rejection of the HIV-positive identity. Each construction entailed an aspect related to the sexual exclusion of those living with HIV, and an aspect related to their social exclusion. The extent to which the lives of those interviewed were affected by stigma was starkly revealed, as was the extent to which they stigmatized others living with HIV and rejected the HIV-positive identity. The research highlights the failure to socially normalize HIV and that interventions are needed to reduce the distress associated with seropositivity.