Streptothricin acetyltransferase was purified from Streptomyces lividans harboring a plasmid which carried the streptothricin-resistance gene cloned from a streptothricin-producing strain, Streptomyces lavendulae No. 1080. Some properties of the enzyme were determined and the reaction product was identified to be N beta-acetylstreptothricin by NMR spectroscopy.