Innovative graft polymers designed for the efficient delivery of antisense molecules into biological cells and for maintaining the biological activity of these molecules while in serum and other aqueous environments are provided. Such polymers may comprise an anionic graft polymer comprising an anionic polymer backbone with pendant carboxylic acid groups and pendant chains comprising amphipathic or hydrophilic polymers covalently bonded to a portion of said pendant carboxylic acid groups. Antisense molecule delivery vectors comprising such polymers in combination with cationic agents for delivery of antisense molecules are also disclosed.