3'-Deoxykanamycin A useful as antibacterial agent is produced from a protected kanamycin A derivative either by a process comprising imidazolylthiocarbonylation of the 3'- and 2"-hydroxyl groups of 4",6"-O-cyclohexylidene-4'-0:6'-N-carbonyl-5,2'-O-isopropylidene-1,3,3"-tri-N-tosylkanamycin A, preferential removal of the 3'-imidazolylthiocarbonyloxy group with tributyltin hydride for the 3'-deoxygenation, followed by removal of the 2"-O-imidazolylthiocarbonyl group with aqueous ammonia, removal of the N-tosyl groups with alkali or alkaline earth metal in liquid ammonia, hydrolytic fission of the 4',6'-cyclic carbamate ring and concurrent removal of the 5,2'-O-isopropylidene group and 4",6"-O-cyclohexylidene group, or by a process comprising selective acetylation of the 2"-hydroxyl group of said protected kanamycin A derivative with acetyl chloride in pyridine, trifluoromethanesulfonylation of the 3'-hydroxyl group, followed by concurrent removal of the 3'-trifluoromethanesulfonyloxy group and N-tosyl groups with alkali metal in liquid ammonia, removal of the 2"-O-acetyl group concurrently with hydrolytic fission of 4',6'-cyclic carbamate, and hydrolytic removal of the 5,2'-O-isopropylidene and 4",6"-O-cyclohexylidene groups.