The synthesis of polyaniline film was achieved on copper electrodes from monomer containing 0.2 M sodium oxalate solution by using a cyclic voltammetry technique. The synthesized film was found to be very adherent and homogeneous. The corrosion performance of PANi coated samples were investigated in 3.5% NaCl solutions by using electrochemical impedance spectroscopy (EIS), anodic polarization curves and open circuit potential-time (E-ocp-t) curves. It was shown that PANi coating could provide important protection against corrosion of copper in such an aggressive medium. The polymer film behaved like a barrier against the attack of the corrosive environment. It was also found that the polymer film by its catalysing effect led to the formation of very protective copper oxides on the surface. (C) 2004 Elsevier B.V. All rights reserved.