The inhibition effect of blue tetrazolium (BT) on the corrosion of cold rolled steel (CRS) in 1.0 M sulfuric acid (H(2)SO(4)) at 20 degrees C was investigated for the first time by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The results show that BT is a good inhibitor and the maximum inhibition efficiency is higher than 94% at 0.10 mM. The adsorption of BT on CRS surface obeys Langmuir adsorption isotherm. Polarization curves show that BT acts as a mixed-type inhibitor. EIS spectra consist of large capacitive loop at high frequencies followed by a small inductive one at low frequency values, and charge transfer resistance increases with the inhibitor concentration. The inhibitive mechanism is proposed from the viewpoint of adsorption theory. (C) 2011 Elsevier BM. All rights reserved.