The inhibitive action of ortho-methoxy substituted polyaniline, a new class of conducting polymer, on the corrosion of iron in acidic chloride solution has been evaluated by Electrochemical Impedance Spectroscopy (EIS), Linear Polarization Resistance (LPR), Weight Loss (WL) and by the Logarithmic Polarization Technique (LPT). Inhibition efficiencies of nearly 80-88% have been observed even at 25ppm concentration. Double-layer capacitance studies indicate a strong adsorption of polymer following the Temkin adsorption isotherm is largely responsible for its inhibitive action.