Adsorption of HMDTMP derivatives on the carbon steel surface is in agreement with the Langmuir adsorption isotherm model, and the calcu- lated Gibbs free energy value confirms the chemical nature of the adsorption. EIS results show that the charge in the impedance parameters (Rt and Cdl) with concentrations of HMDTMP is indica- tive. The adsorption of this molecule leads to the formation of a protective layer on carbon steel surface. The electrochemical results have also been supplemented by surface morphological studies.