Aims: Characterization and purification of a new bacteriocin produced by Lactobacillus plantarum LP 31 strain, isolated from Argentinian dry-fermented sausage. Methods and Results: Lactobacillus plantarum LP 31 strain produces an antimicrobial compound that inhibits the growth of food-borne pathogenic bacteria. It was inactivated by proteolytic enzymes, was stable to heat and catalase and exhibited maximum activity in the pH range from 5.0 to 6.0. Consequently, it was characterized as a bacteriocin. It was purified by RP (reverse-phase) solid-phase extraction, gel filtration chromatography and RP-HPLC. Plantaricin produced by Lact. plantarum LP 31 is a peptide with a molecular weight of 1558.85 Da as determined by Maldi-Tof mass spectrometry and contains 14 amino acid residues. It was shown to have a bactericidal effect against Pseudomonas sp., Staphylococcus aureus, Bacillus cereus and Listeria monocytogenes. Conclusions: The bacteriocin produced by Lact. plantarum LP 31 may be considered as a new plantaricin according to its low molecular weight and particular amino acid composition. Significance and Impact of the Study: In view of the interesting inhibitory spectrum of this bacteriocin and because of its good technological properties (resistance to heat and activity at acidic pH), this bacteriocin has potential applications as a biopreservative to prevent the growth of food-borne pathogens and food spoilage bacteria in certain food products.