Bi-layered composites of polyaniline (PANT) and poly(o-anisidine) (POA) were investigated for corrosion protection of low carbon steel (LCS). In this work, homopolymers and bi-layers of PANT and POA were electropolymerized on LCS from an aqueous salicylate solution by using cyclic voltammetry. These coatings were characterized by cyclic voltammetry, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Corrosion tests were carried out in aqueous 3% NaCl solution for LCS coated with PANT, POA, bi-layered POA/PANI (POA on top of the PANT) or PANI/POA (PANT on top of the POA) composites using open circuit potential (OCP) measurements, potentiodynamic polarization technique, and electrochemical impedance spectroscopy (EIS). The single layer of PANT and POA protected the LCS in 3% NaCl for 8 and 16 h, respectively. The bi-layered composite coatings provide effective protection to LCS for a longer time than a single layered PANT or POA coating. However, the corrosion protection offered to LCS depends on the deposition order of polymer layers in the composite. The PANI/POA composite provides better protection to LCS against corrosion than POA/PANI coating. (C) 2008 Wiley Periodicals, Inc.