Abstract: Lactoferricin (Trade Mark), also called LFCIN (Trade Mark), a potent antimicrobial peptide, is produced by contacting an enzymatic hydrolysate of bovine lactoferrin or any mixture of peptides containing lactoferricin preferably with a butyl moiety-containing hydrophobic interaction chromatography medium, or alternatively with a carboxymethyl moiety-containing cation-exchange chromatography medium, rinsing the medium to remove unbound peptides, desorbing the lactoferricin solution at constant pH, and desalting the desorbed solution. The utility of the process is illustrated, for example, as follows. An enzymatic hydrolysate of bovine lactoferrin (600 g) was contacted with 3000 ml of BUTYL-TOYOPEARL 650M, the medium was rinsed with water, and then with McIlvaine (citric acid-sodium phosphate) buffer at pH 7.0., and lactoferricin was desorbed with McIlvaine buffer at pH 5.0.