We investigated the association between human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV) infections in 593 homosexual men. The status of EBV infection in this group was evaluated based on serological evidence of EBV-specific antibody responses. The geometric mean titers (GMT) of antibody to EBV capsid antigen (EBV-VCA) (1:154) and EBV early antigen (EA) (1:16) in 141 HIV-seropositive men were significantly higher than respective titers in 452 HIV seronegative men (1:95 and 1:12). Antibody titers to EBV were higher in HIV-infected men with lymphadenopathy than in asymptomatic HIV-seropositive men. However, these correlation were less evident in patients with AIDS-related complex. Elevated antibody titers to EBV were found to be independent of levels of total serum IgG. Cytomegalovirus (CMV) antibody titers were also found to be significantly increased among HIV-seropositive men, independent of total IgG. Antibody titers to EBV were not correlated with those to CMV in either HIV-seronegative or HIV-seropositive men. Subjects without evidence of HIV infection, but who had high antibody titers to EBV-VCA and EBV-EA, had elevated mean numbers of CD3+, CD4+, and CD8+ cells, and lower levels of CD4+/CD8+ cell ratios compared to subjects with low EBV-antibody titers. This study suggests that the elevated levels of circulating antibodies against EBV in homosexual men are associated with loss of control of latent EBV due to HIV infection.