The significance of serum IgG and IgA antibodies to cytomegalovirus (CMV) at various stages of human immune deficiency virus (HIV) infection was studied in 175 homosexual men. Sera were obtained from 123 HIV seropositives [41 asymptomatic, 29 with lymphadenopathy associated syndrome (LAS), 22 with AIDS related complex (ARC), and 31 AIDS patients], 17 HIV seroconverters, and 35 HIV asymptomatic seronegatives. The sera were tested blindly for CMV IgA and IgG antibodies using the immunoperoxidase assay (IPA) and CMV infected human embryo cells. Crossectional analysis of CMV IgG antibodies at a titer of ⩾20 showed 87% and 100% prevalence in the HIV seronegative groups and in the HIV seropositive groups, respectively (P < 0.05). CMV IgG antibodies at a titer of ⩾80 were present in significantly higher proportions among the HIV seropositive subjects of the various groups as compared with the HIV seroneg‐ ative homosexual men. However, in the HIV seronegatives who later seroconverted to HIV, a significantly higher prevalence of CMV antibodies (35%) was detected before HIV seroconversion, as compared with the persistently HIV seronegative subjects (14.3%) (P < 0.05). The HIV seronegatives pre‐HIV seroconversion also exhibited a significantly higher geometric mean titer (GMT) of CMV IgG antibodies (62.17 ± 0.64) as compared with the persistently HIV seronegatives (34.0 ± 0.6) (P = 0.03). Significantly higher GMTs of CMV IgG antibodies were detected in all the HIV seropositive groups as compared with the persistently HIV seronegativegroup. CMV IgG antibodies were not detected in the HIV seronegative subjects. CMV IgA antibodies were found in 5.9% of the HIV seroconverters, i n 19.5% of the HIV seropositive asymptomatic subjects, 34.5% of LAS, 22.7% of ARC, and 6.5% of AIDS patients. These data support the concept that CMV might be associated with susceptibility of homosexual men to HIV infection and disease progression.