The summarized results of the observations of 449 hospitalized patients, aged mainly 18-37 years (40 patients with active AIDS, 43 patients with AIDS, other patients were HIV carriers and infected at the stage of lymphadenopathy). In most of the HIV-infected patients the infection process progressed in 3-5 years, which was manifested by associated candidiasis in 74.7% of cases. In AIDS patients opportunistic infections of viral etiology (herpes simplex, cytomegalovirus infection, etc.) prevailed. 14 patients were found to have tuberculosis. Clinico-epidemiological analysis made it possible to come to the conclusion that the specific features of HIV carriership and AIDS were greatly linked with different groups of risk to which the patients belonged. Thus, a shorter period of carriership, the prevalence of opportunistic viral infections were mostly characteristic of drug addicts.