Judging by the physical and chemical properties and “bacterial spectra”, the antibiotic substance, Enniatin, previously isolated from a strain ofFusarium by the authors, appears to be identical with that which was recently reported byCook et al. derived from another strain and designated by them as Lateritiin-I, although the reported empirical formulae differ. Numerous physical and chemical characteristics of Enniatin and its degradation products are given, and, further, two relatedFusarium antibiotics, here designated as Enniatin B and C, are briefly described.