The anti-corrosion performance of polyaniline-thiokol rubber (PANI/TR) composite coating covered on mild steel exposed to artificial brine and hydrochloric acid environments was evaluated for the first time. The PANI/TR composite coatings were electropolymerized and deposited on mild steel in a nonaqueous solution. EDS, XPS and SEM were all used to characterize the structure as well as the component of the PANI/TR composite coating, which has indicated that its structure would be favorable to the corrosion protection. The results of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) demonstrated that the PANI/TR coating was much better than polyaniline (PANI) coating both in the adhesion to the mild steel substrate and in the corrosion protection. The corrosion potential was about 100 mV more positive for the substrate coated with PANI/TR film than that with PANI. As a result, the corrosion of mild steel can be inhibited greatly by using the PANI/TR composite conductive polymer as a protective layer. (C) 2002 Elsevier Science B.V. All rights reserved.