The aim of the present paper was to determine the effect of bacteriocins produced by Lactobacillus strains isolated from pickled vegetables on Gram-negative pathogenic rods. The antibacterial effect of bacteriocins was determined with the diffusion method, employing the well technique. Incubation was carried out for 24 hours, under the optimum conditions for test strains, and then growth inhibition zones around wells were observed. The results obtained show that individual Lactobacillus strains produce antibacterial substances - bacteriocins, characterized by different activity towards selected strains of Yersinia enterocolitica, Salmonella E. coli O 157.H7 and E. coli K88. Test strains were more sensitive to bacteriocins synthesized by Lactobacillus plantarum, as their growth was inhibited at the activity level 4-32 AU/mL. Bacteriocins of Lactobacillus brevis strains inhibited their growth at 128 and 256 AU/mL.