Lactobacillus spp., as probiotics bacteria, are being increasingly studied for theirinhibitory activity against pathogenic bacteria. There is some evidence that they are noteffective against gram-negative bacteria. The objective of this study was to investigatethe antagonistic activity of Lactobacillus plantarum PTCC 1058, Lactobacillusdelbrueckii sub.sp bulgaricus PTCC 1737 and Lactobacillus leichmannii PTCC 1057against antibiotic resistance Salmonella typhimurium. The Salmonella typhimuriumstrains were identified by biochemical tests, antisera and multiplex PCR assays.Subsequently, the anti-bio gram against ten Salmonella typhimurium strains wasinvestigated using six commonly-used antibiotics. The antibacterial effect ofLactobacillus spp. was evaluated by the means of Agar disk-diffusion and Agar welldiffusionassays. This in vitro study implied that none of the Lactobacilli hadantibacterial effect against Salmonella typhimurium strains, so they are not suggested to be used asalternative treatment instead of administration of antibiotics to control S.typhimurium.