97 symptom-free homosexuals were studied clinically, serologically, and with in-vivo and in-vitro tests of cellular immune function in the context of the acquired immunodeficiency syndrome (AIDS). A high proportion of these men showed abnormalities: lymphopenia (33%), decreased T-helper/T-suppressor (Th/Ts) cell ratios (43%), both these abnormalities (12%), decreased total T-helper cells (15%), monocyte chemotactic (10%) and phagocytic (27%) defects, anergy to three recall antigens (32%), and anergy to purified protein derivative despite BCG inoculation (55%). The lymphocyte abnormalities and anergy characteristic of AIDS were seen in 5%. No clear clinical or serological associations were seen for the AIDS-like defects. Trends of association were seen between higher lymphocyte counts, lower Th/Ts ratios, more T-suppressor cells and serological evidence of previous virus infection. The combination of lymphocyte abnormalities and anergy observed in these symptom-free homosexuals may represent a latent phase of AIDS.