The application of 2-amino-4-methyl-thiazole (2A4MT) as a corrosion inhibitor for mild steel (MS) protection was investigated in 0.5 M HCI solution. The electrochemical impedance spectroscopy and potentiodynamic measurements were used at various concentrations and temperatures. The surface of MS was analyzed with scanning electron microscope in absence and presence of 2A4MT. Results showed that the correlation between experimental (inhibition efficiency, surface charge, Delta G degrees(ads), E-a) and quantum calculation parameters (dipole moment, E-HOMO, E-LUMO). It was concluded that the high corrosion inhibition efficiency of 2A4MT was associated with its strong adsorption as a barrier film on the MS surface. (C) 2014 Elsevier Ltd. All rights reserved.