A molecularly imprinted polymer (MIP) membrane for sensing O,O-dimethyl-alpha-hydroxylphenyl phosphonate (DHP) has been prepared by electropolymerizing o-phenylenediamine on the glassy carbon electrodes in the presence of DHP. Optimization studies with the aim to enhance insulating properties and response kinetics of the polymer membrane were carried out with respect to template molecular concentration, the monomers concentration, the polymer membrane thick and scan rate. Cyclic voltammetry and electrochemical impedance have been used to characterize the behavior of MIP polymer membrane. The capacitive measurements were also certified the imprinting effect of the polymer layers. The experimental results showed that DHP imprinted polymer has better recognition property for the template than that of a blank polymer. (c) 2006 Wiley Periodicals, Inc.