The corrosion behavior of mild steel (MS) in 0.5 M H2SO4 was studied using 3-[(2-hydroxy-benzylidene)-amino]-2-thioxo-thiazolidin-4-one (HBTT) as inhibitor using the conventional potentiodynamic polarization studies, linear polarization studies (LPR), electrochemical impedance spectroscopy studies (EIS). SEM was utilized for surface characterization. The results showed that HBTT posses excellent inhibition effect towards MS corrosion. The inhibitor molecules were first adsorbed on the MS surface and blocking the reaction sites available for acid attack. Adsorption of inhibitor was found to obey Langmuir isotherm and was more chemical than physical. (C) 2012 Elsevier Ltd. All rights reserved.