Grafted copolymer of poly(vinyl chloride) (PVC) with N-isopropylacrylamide (NIPAAm) was prepared by radiation-grafting method using gamma-ray source. NIPAAm was graft polymerized from its aqueous solution onto PVC tubes by preirradiation method, all samples were exposed in the presence of air at room temperature to Co-60. Conditions for achieving maximum grafting yield were observed between 0.5 and 1 moldm(-3) of monomer concentration, pre-irradiation dose of PVC from 5 to 110 kGy, and reaction temperature of 323 and 333 K. Characterization of the grafted copolymer was conducted by various methods: FTIR-ATR, TGA, and SEM. The temperature-responsive behavior of grafted copolymer was studied by swelling at various temperatures and pH 6.8.