h i g h l i g h t s We have identified corrosion of carbon steel in hydrochloric acid with Molasses extract. We found that inhibition efficiency of 6000ppm molasses concentration is around 90%. The relation of two simultaneous techniques: DEIS and volumetric, was described. a b s t r a c t The inhibition effect of molasses on the corrosion of low carbon steel in 1M hydrochloric acid solution was investigated by volumetric and electrochemical measurements. Potentiodynamic polarization and dynamic electrochemical impedance spectroscopy (DEIS) results were obtained and compared with to those, obtained with the hydrogen evolution technique. All results indicate that molasses functioned as a good inhibitor in 1M hydrochloric solution and inhibition efficiency increased with molasses concen-tration. The advantage of DEIS as a tool for investigation of molasses influence was discussed.