Two ionic liquids, 1,3-dibencilimidazolio acetate (DBImA) and 1,3-dibencilimidazolio dodecanoate (DBImL), were investigated as corrosion inhibitors in 1.0 M HCl and H2SO4 solutions. The data extracted from Tafel plots, electrochemical impedance spectroscopy and SEM indicate a high inhibition effectiveness in HCl solution. A dense layer of physisorbed inhibitor prevents the diffusion of ionic species from the film and/or the attack of the surface by ions in solution. The protection efficiency increases as the concentration of the inhibitors increases. The adsorption of these inhibitors on steel surfaces obeys the Langmuir isotherm. (C) 2014 Elsevier B.V. All rights reserved.