Hydrogen evolution reaction (HER) (cathodic reaction) of mild steel immersed in H(2)SO(4) acid was investigated. Electrochemical corrosion behavior and hydrogen evolution reaction of mild steel has been investigated using different electrochemical techniques. Steel was polarized vs. saturated calomel electrode (SCE) in naturally aerated 1.0 M H(2)SO(4) aqueous solution containing four organic inhibitors (newly synthesized heterocyclic compounds) of different concentrations. The observed different influence of corrosion inhibitors on the hydrogen evolution reaction was associated with the different chemical composition and structure. Polarization results showed that corrosion current density, i(corr) and hydrogen evolution decreases with increasing concentration of inhibitors in 1.0 M H(2)SO(4), indicating a decrease in the corrosion rate. Electrochemical impedance spectroscopy (EIS) measurements confirmed this behavior. An increase of temperature leads to increase in the corrosion or hydrogen evolution rate and a decrease of the total resistance value, R(T). The obtained results were confirmed by surface examination. Published by Elsevier Ltd on behalf of Professor T. Nejat Veziroglu.