The reduction of corrosion and hydrogen permeation through mild steel in 0. 5M H2SO4 and 1M HCl has been studied using weight loss measurements and various electrochemical techniques in the presence and absence of a green inhibitor viz., Carbenicillin(CBN). The inhibitor is found to be more inhibitive in H2SO4 than in HCl. Potentiodynamic polarization studies clearly justify the fact that this compound acted as a mixed inhibitor; but predominantly as a cathodic inhibitor. Hydrogen permeation studies and AC impedance measurements also confirm the improved performance of the compound in H2SO4. The adsorption of this compound on the mild steel surface follows Temkin’s adsorption isotherm. © 2015 University of Manchester and the authors.