The corrosion inhibition of mild steel in 1 mol.L-1 hydrochloric acid by N-methyl-2-(2-nitrobenzylidene) hydrazine carbothioamide (MNBHC) was studied using weight loss and electrochemical studies. Results obtained indicate that the inhibitor is effective in hydrochloric acid medium and the efficiency decreases with increase in temperature. Added halide additives improve the efficiency of the inhibitor. The AC impedance studies reveal that the process of inhibition is through charge transfer. Polarization studies indicate the mixed nature of the inhibitor. From the thermodynamic, spectral and surface analyses the nature of adsorption has been found out. The adsorption of the inhibitor on mild steel follows the Langmuir isotherm. (C) 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.