We compared the immunogenicity of recombinant S. pneumoniae pneumolysin (rPly) when administered with and without Al(OH) 3 adjuvant, and evaluated the protective properties of recombinant protein in the active defense experiment. It was shown that double immunization with rPly+Al(OH) 3 increases the levels of IgG antibodies in comparison with the control ( p <0.01), while triple immunization results in a more significant increase in IgG antibody levels ( p <0.001). Double immunization with rPly without Al(OH) 3 does not induce a significant increase in antibody levels in comparison with the control, while triple immunization results in a slight but significant increase in antibody levels ( p <0.05). The active defense test proved the protective activity of rPly against S. pneumoniae serotype 3 at intranasal infection.