Polyaniline (PANT), poly(2-chloroaniline) (PCIANi), and poly(aniline-co-2-chloroaniline) (co-PCIANi) films were synthesized by electrochemical deposition on 304-stainless steel (SS) from an acetonitrile solution. The structural properties of these polymer films were characterized by spectroscopic (FTIR and UV-vis) and electrochemical (cyclic voltammetry) methods. Open circuit potential-time (E-ocp - time) curves, potentiodynamic polarization, and electrochemical impedance (EIS) measurements showed that these films have significant protective performance against corrosion of SS in 0.5 M HCl solution. It was found that co-PCIANi film has acted as a passivator as well as barrier for cathodic reduction reaction in a similar manner as PANT film. However, PCIANi film has behaved only as barrier for corrosion protection of SS in 0.5 M HCl. (C) 2006 Elsevier B.V. All rights reserved.