The iron plate covered with films of polyaniline-coated polystyrene latex (PANI-PS) microspheres were protected against corrosion in 0.01 mol dm(-3) HCl and 3% (w/v) NaCl aqueous solution. PANI-PS particles 1.85 +/- 0.06 mu m in diameter were synthesized by polymerizing chemically aniline on polystyrene (PS) latex in the suspension. The conducting state (emeraldine salt) of PANI film shifted the corrosion potential of the underlying iron toward a positive from the insulating state of PANI (leucoemeraldine form). The film from which core-polystyrene was removed by dissolution in tetrahydrofuran had the similar anti-corrosive properties. Tafel plots, open circuit potential-time diagrams were used to examine the corrosion properties of PANI-PS coated and uncoated electrodes. (C) 2005 Published by Elsevier B.V.