The corrosion inhibition properties of ceftadizime (CZD) for mild steel corrosion in HCl solution were analysed by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and gravimetric methods. These results were supplemented by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Mixed mode of adsorption (physisorption and chemisorption) is proposed for the inhibition and the process followed the Langmuir adsorption isotherm and kinetic/thermodynamic model of El-Awady et al. The mechanism of adsorption inhibition and type of adsorption isotherm were proposed from the trend of inhibition efficiency with temperature, E(a) and Delta G(ads)degrees. Potentiodynamic polarization study clearly revealed that CZD acted as mixed type inhibitor. The experimental data showed a frequency distribution and therefore a modelling element with frequency dispersion behaviour and a constant phase element (CPE) have been used. (C) 2011 Elsevier B.V. All rights reserved.