The inhibition of three ethoxylated fatty acids of different molecular weights on the corrosion of aluminum in both 1.0 M HCl and 1.0 M H2SO4 solutions have been studied at different temperatures (25-55 degreesC) by means of weight loss and potentiodynamic polarization techniques. The inhibition efficiency for the three fatty acids increase with the increase in the inhibitors concentration but decreases with increasing temperature. The inhibition efficiency for the three inhibitors decreases in the order (n = 20, 40, 80): OL[EO]80 > OL[EO]40 > OL[EO]20 The inhibition occurs through adsorption of the inhibitor molecules on the metal surface without modifying the mechanism of corrosion process. Frumkin adsorption isotherms fit well the experimental data of dissolution and adsorption were calculated and discussed. (C) 2003 Elsevier B.V. All rights reserved.