AIM To measure level of antibodies to pneumococcal antigens in HIV-infected children vaccinated in the age > 2 y.o. in order to assess clinical effect of vaccination. MATERIALS AND METHODS Levels of IgG and IgM were measured by ELISA in 16 HIV-infected children > 24 months of age vaccinated against pneumococcal infection with Pneumo 23 vaccine on IIA-B stage of the disease. When the study was conducted, children did not receive antiretroviral therapy. Control group was represented by 47 children of the same age born from HIV-negative women. RESULTS It was determined that HIV-infected children had high baseline levels of IgG and IgM to antigens of Streptococcus pneumoniae to 2 years of age, which is indirect evidence of previous pneumococcal infection. Increase of antibody levels after vaccination to polysaccharides (PS) of S. pneumoniae serotypes 3, 6B, 9N, 23F as well as to mix of PS included in the vaccine was not observed compared to the control group. Despite the absence in dynamics of IgG and IgM levels, decrease of acute respiratory, infections incidence on 34.6 - 36.4% was noted in HIV-infected participants during 1-year follow-up, which can be associated with immunocorrecting effect of PS contained in the Pneumo 23 vaccine. It was assumed that significant clinical and immunological effect of vaccination could be obtained by administration of pneumococcal conjugate vaccine in younger age, before realization of HIV-infection. CONCLUSION Vaccination against pneumococcal infection is indicated for HIV-infected children; it promotes decrease of rate of intercurrent infections on the background of the main disease.