Guanadinylated aminoglycoside-lipid conjugates are prepared. Such conjugates may comprise an aminoglycoside such as an aminoglyucoside antibiotic like neomycin or kanamycin, at least one guanidino group attached to a primary or secondary carbon atom of the aminoglyucoside group and at least one lipid group attached through a bond or a linker to a branched carbon atom of the aminoglycoside. These conjugates exhibit improve antibacterial activity and may be used in conjunction with another antibiotic.