Azinothricin was isolated from the culture filtrate of Streptomyces sp. X-14950 in crystalline form. It represents a new type of hexadepsipeptide antibiotic as it contains a 19-membered cyclodepsipeptide ring composed of six unusual amino acids and bearing a novel C21 side chain. Azinothricin was identified as [(3S,4S,7R(S*),10S,17R,20S,23R)[2S(2''R*,5''S*,6''S*)3S*]]-.alpha.-ethyl-6-(3-ethyl-1,5-dimethyl-4-oxo-1,5-heptadienyl)-N-(1,8,14,15,18,21,27-heptaaza-21-hydroxy-7-(1-hydroxyethyl)-2,6,9,16,19,22-hexaoxo-4-isopropyl-20-(methoxymethyl)-17,18-dimethyl-5-oxatricyclo[21.4.0.010,15]heptacosan-3-yl)tetrahydro-.alpha.,2-dihydroxy-5-methyl-2H-pyran-2-acetamide and is primarily active agaisnt Gram-positive microorganisms.