Iturin A, an antifungal lipopeptide characterized by the presence of homologous liposoluble beta-aminoacids was found to be the active component to bacillomycin B, bacillomycin R and eumycin. Iturin A was identified by thin-layer chromatography, aminoacid analysis and by characterization of liposoluble aminoacids and peptides. Another two preparations: the antibiotic of Raubitschek and the bacillomycin of Landy et al. contain components of the same structural type but they are different from iturin A.