Lactic acid bacteria are a group of Gram-positive microorganisms widely used in food preservation due totheir probiotic properties and their ability to produce bacteriocins. Bacteriocins are antibiotic compoundsof peptide nature which have been studied intensively for their potential use as substitutes of chemicaladditives in food preservation. In this paper we report the isolation and characterization of Lactobacillusplantarum LPBM10. This bacteriocin was isolated from fermented milk and can be classified as probiotic.The free cell extract was active against Gram positive and Gram negative bacteria. This bacteriocin ishighly thermostable, active at low pH and its activity is not affected by proteinase K, chelating agentsand detergents. This antibiotic compound was purified by dyalisis and size exclusion chromatography.Its analysis by UV and FT-IR spectroscopy suggests that bacteriocin is a peptide containing some cysteinand tyrosine aminoacids. Experiments on dyalized crude extract by ion-exchange chromatography suggestthe presence of an anionic inhibitor of LPBM10.