A novel molecularly imprinted polymer (MIP), poly(pyrrole-co-o-phenylenediamine) (p(Py-co-OPD)), has been developed in order to construct an enrofloxacin (EF) sensor by using cyclic voltammetry (CV) technique. The preparation conditions including the pH level, EF concentration, the number of CV cycles, extraction solution of the template and the incubation time were optimized. The performance of the MIP sensor was evaluated by square wave voltammetry (SWV). Under the optimal experimental conditions, the MIP sensor exhibited long time stability, good selectivity and a wide linear range of 1.0 x 10(-4)-1.0 x 10(-10) mol/L with a low detection limit of 6.57 x 10(-13) mol/L towards EF. Moreover, the sensor was successfully used to determine the EF amount in the pharmaceutical samples with satisfactory results.