Imprinting polymerization is used to make resins with a high capacity for cadmium ions for waste-water treatment. A random copolymer of methacrylate and methacrylamide was found to be most effective, especially when the porosity of the resin is increased. Complete removal for up to 80 ppm of cadmium with only 50 mg of resin was demonstrated with the imprinted resins, but not the nonimprinted reference samples. This shows that imprinting polymerization improves the capacity of the resin in the uptake of cadmium ions. (c) 2007 Wiley Periodicals, Inc.