A new antibiotic termed zelkovamycin was isolated from the fermentation broth of Streptomyces sp. K96-0670 by solvent extraction, ODS column chromatography and preparative HPLC. Zelkovamycin showed antibacterial activity against Xanthomonas oryzae, Acholeplasma laidlawii, Pyricularia oryzae and Staphylococcus aureus.