Abstract: The present invention provides a composition of matter useful as an antimicrobial agent. This composition of matter comprises at least two polypeptides selected from the group consisting of human polymorphonuclear leukocyte, polypeptides having on apparent molecular weights of about 3,500 daltons, about 13,000 daltons, about 18,000 daltons, about 29,000 daltons, and about 54,000 daltons. The composition of matter has respiratory burst-independent, antimicrobial activity for bacteria and fungi at a pH from about 5.0 to about 8.0 and at calcium ion concentrations up to about 10 mM, bactericidal activity at sodium chloride concentrations up to about 0.3M, and fungicidal activity at sodium chloride concentrations up to about 0.15M. Methods for preparing this composition of matter are also provided. Further provided are purified polypeptides useful as antimicrobial agents, and methods for producing these polypeptides.