WAC04657 is a wild-isolate Streptomyces that has antibiotic activities against multidrug-resistant Gram-negative and Gram-positive pathogens. From a solid-agar culture of this organism we isolated 13-deoxytetrodecamycin, a novel antibacterial molecule. It is one of at least three distinct antimicrobial compounds produced by this strain. The molecule has the molecular formula C 18 H 22 O 5 and is related to the previously discovered compound tetrodecamycin. 13-Deoxytetrodecamycin has potent bioactivity against Gram-positive pathogens including multidrug-resistant Staphylococcus aureus.