OBJECTIVE Previous research has indicated that the concealment of homosexuality is related to poorer health among gay men with HIV. This study explored mechanisms by which concealment of homosexuality may be related to HIV disease status by examining associations between concealment of homosexuality, social support, social constraints, depressive symptoms and CD4 count among HIV-seropositive gay men. METHOD Questionnaires assessing concealment of homosexuality, social support, depressive symptoms and social constraints were administered to 73 HIV-seropositive gay men. Medical charts were accessed to gather HIV disease information including CD4 counts. Regression analyses were conducted to examine associations between psychosocial variables and CD4 counts. RESULTS Concealment of homosexuality was associated with lower CD4 count, greater social constraints, greater depressive symptoms and less social support. The association between concealment of homosexuality and CD4 count varied according to level of social support. Among participants with higher levels of social support, those with greater concealment had lower CD4 counts than those with lower concealment. Concealment of homosexuality was not related to CD4 count among participants reporting low social support. CONCLUSION Concealment of homosexuality among HIV-seropositive gay men is associated with lower CD4 counts, depressive symptoms and strained social relationships. In addition, the benefits of being open about homosexuality may be most evident under conditions of greater social support.