Surface modification of argon plasma-pretreated poly(tetrafluoroethylene) (PTFE) film by UV-induced graft copolymerization with 4-vinylaniline (4-VAn), followed by oxidative copolymerization of the aniline moiety of the grafted 4-VAn polymer with aniline, was carried out to render the PTFE surface conductive. The surface compositions of the graft-modified PTFE films were studied by X-ray photoelectron spectroscopy (XPS). The yield of the initially grafted 4-VAn polymer increased with increasing monomer concentration and UV graft copolymerization time. The efficiency of the subsequent surface oxidative copolymerization with aniline (and thus the resulting surface conductivity) was enhanced by the high concentration of the 4-VAn polymer from the initial graft copolymerization. The surface resistivity of the PTFE films was reduced to the order of 10(6) Omega/square by the two consecutive surface graft copolymerization processes. The doping-undoping (protonation-deprotonation) behavior of the surface graft copolymerized aniline polymers was similar to that of the aniline homopolymer or polyaniline (PAn).