Individual features of sensitivity of some strains of group B streptococci (GBS) to influence of 2 probiotic cultures of Enterococcus faecium (SF68 and L3) have been studied by double agar test. E. faecium L3 strain had higher antagonistic activity to GBS. Two genes encoding enterocins A and B as well as genes responsible for the expression of the former two genes were found in the genome of this strain. The supernatant and peptide extract of E. faecium L3 contained thermostable low molecular weight peptides which inhibited growth of listeria and GBS but at lesser extent compared with native enterococci. Obtained data allow to suggest that antagonistic activity of enterococci against GBS may be affiliated with production of enterocins A and B and can be increased by the presence of other metabolites.