Synthetic polymers capable of atrazine-selective decomposition were prepared by molecular imprinting. A combinatorial approach was employed using an automated polymer preparation/evaluation system for the selection of functional monomers to construct the atrazine decomposition sites. Combined use of methacrylic acid and 2-sulfoethyl methacrylate provided atrazine-decomposing polymers in which atrazine was converted to a non toxic compound atraton and the imprinting effects enhanced the catalytic activity.