A chlorpyrifos (CPF) templated molecularly imprinted film was electrochemically synthesized on a pencil graphite electrode (PGE) by electropolymerization of pyrrole (Py) in the presence of CPF. The fabricated modified electrode was used as a novel impedimetric sensor for the determination of an important organophosphorus pesticide, CPF. The binding performance of CPF toward the polypyrrole (PPy) film was examined using electrochemical impedance spectroscopy (EIS). The surface morphology of the imprinted film was characterized by scanning electron microscopy (SEM). Results obtained from the impedance measurements show that imprinted PPy modified PGE offers a disposable, low cost, selective and sensitive electrochemical sensor for the determination of CPF. Under experimental conditions, the proposed impedimetric sensor has a linear response range from 20 to 300 mu g L-1 CPF with a detection limit of 4.5 mu g L-1 (based on 3(sb)). Furthermore, the fabricated sensor was successfully applied to determine CPF in CPF-added artificial samples. (C) 2013 Elsevier B.V. All rights reserved.