The 6'-N-acetyltransferase derived from Streptomyces kanamyceticus strain M1164 was cloned on to the high copy plasmid vector pIJ702 and introduced into S. kanamyceticus (ATCC 12853, a kanamycin producer) and S. fradiae (ATCC 10745, a neomycin producer). In both cases transformants containing the recombinant plasmid showed increased resistance to a number of aminoglycoside antibiotics and substantially increased production of kanamycin and neomycin. This demonstrates that specific amplification of gene products associated with antibiotic biosynthesis provides a means for improving antibiotic production.