Currently, in human medicine and veterinary medicine, the urgent issue of finding drugs that can become an alternative to antibiotics, will be created on the basis of living bacteria and are able to slow down the growth of pathogenic and opportunistic microorganisms that can acquire resistance to antibiotics. Now, it is important to find new substances that will act against pathogens and at the same time have a positive effect on the microflora of living macroorganisms. The aim of our scientific work was to study the morphological features, determine the biochemical properties of bacteria of the genus Lactobacillus, isolated from meat, food additives, starter cultures and intestines of laboratory animals; research of their antagonistic effect on epizootic and laboratory strains of microorganisms. The research was carried out using methods generally accepted in microbiological practice and statistical data analysis. Selected isolates were identified: L. delbrueckii; L. fermentum; L. bulgaricus; L. curvatus; L. casei subsp. tolerans. Study of antagonism was conducted on epizootic (Pseudomonas aeruginosa, Enterocoсcus faecium, Enterocoсcus faecalis, Klebciella ozaenae) and laboratory (Escherichia coli ATCC No 25923, Proteus vulgaris НХ 19222, Bacillus subtilis АТСС No6633, Staphylococcus aureus UNCSM-017) strains of microorganisms. Cultures of lactobacilli isolated from the meat and intestines of laboratory rats and identified as L. curvatus and L. casei subsp. tolerans, synthesize antimicrobial peptides (bacteriocins) that inhibited the growth of a greater number of pathogens (for example: zone of growth inhibition for Staphylococcus aureus was 12.1 and 9.64 mm). During the research had difficulties with the accumulation of lactobacilli: were isolated very difficult, because they needed a special cultivation conditions and composition of substances in the nutrient medium. Lactobacilli are promising microorganisms because they produce bactericidal bioactive agents that can become an alternative to antibiotics or completely replace them; used in the treatment of infectious diseases of humans and animals; safely preserve food products. Isolating and identifying pure cultures of some strains of Lactobacillus bacteria for further investigation of their antimicrobial activity, we will be able to obtain an organic, effective, and most importantly, safe treatment. Key words: lactobacilli, microorganisms, isolates, pathogens, bacteriocins.