Crosslinked polyelectrolyte multilayer membranes are synthesized with salt rejection values approaching those of commercial desalination membranes, but with increased chlorine resistance. The membranes are fabricated directly onto porous commercial substrates. Subsequent crosslinking of the polycation layers with glutaraldehyde leads to NaCl rejections of up to 97%, while the incorporation of a highly sulfonated polysulfone polyanion leads to high chlorine resistance.