Gamma radiation-induced a template copolymerization of acrylic acid (AA) with dimethylaminoethyl methacrylate (DMAEM) on polyacrylamide as a template polymer in the presence of N,N’-methylenediacrylamide (DAM) as a crosslinker was studied by a free radical mechanism for the preparation of poly(amido-amine) resin such as: poly(acrylamide-acrylic acid-dimethylaminoethyl methacrylate) p(AM-AA-DMAEM). The effect of experimental conditions such as concentration of DAM, polymer/monomer ratio, comonomers concentration, comonomers composition and radiation dose on the capacity of the resin toward Cu²⁺ as a test ion was studied.