Polyoxins A-M have been isolated from the culture filtrate of Streptomyces cacaoi var. asoensis. 1) More recently, a newly isolated soil streptomycetedesignated as Streptomyces piomogemd') was found to produce polyoxins Land M. In addition, this strain has been found to produce a minor component, polyoxin N (1).3). In this paper, we wish to describe the isolation, structure, and biological activity of this new member of the polyoxin family.