Influenza is an acute infectios epidemic disease of the respiratory system. It is particularly dangerous for immunodeficient people, including HIV-infected patients. The aim of the study is to evaluate the effectiveness of influenza vaccination in HIV-infected people and to perform a control analysis of the influence of additional demographic, clinical, and laboratory factors on the effectiveness of vaccination. The work also aimed to assess the impact of influenza vaccination on the incidence of bacterial infections of the respiratorysystem. The study was conducted in a group of 47 HIV-infected adults. The control group consisted of 31 healthy adult seronegative volunteers. The study patients and control subjects were vaccinated with inactivated trivalent influenza vaccine of the composition in accordance with WHO recommendations for the given season. The humoral response was assessed in the form of hemagglutinin antibody titers against strains AH1N1, AH3N2 and B. Vaccination against influenza induced significant anti-hemagglutinin antibody titers in all subjects. Despite the weaker immune response in the group of infected people than those in the group of uninfected people, influenza vaccination seems to be moderately effective in HIV-infected patients. Factors such as the age and gender of patients, the level of viremia, CD4 cell count, the stage of the disease according to ; CDC classification, and HCV co-infection had no impact on the effectiveness of vaccinations. It was found that a response to influenza type B antigens was weaker. A review of medical records found no complication, such as bacterial pneumonia.