The corrosion resistance of mild steel in 1 M H2SO4 solution was evaluated after addition of Sn2+ and Zn2+, N-acetylcystein (ACC) and S-benzylcystein (BzC) as a function of concentration (5-1000 mu M) and solution temperature (35-50 degrees C). Eight blends were also investigated. Both polarization resistance (R-p) and electrochemical impedance spectroscopy (EIS) were employed. For single additives, Zn2+ ions acted as accelerator for mild steel corrosion while the other additives showed good performance. The most effective additive was Sn2+. Adsorption of Sn2+, ACC and BzC obeyed the Temkin adsorption isotherm and had a very high negative value of free energy of adsorption (-Delta G(ads)degrees). All blends provided good inhibition which increased with rise in temperature. Corrosion kinetic parameters such as activation energy (E-a) and the pre-exponential factor (lambda) were calculated and discussed. EIS revealed that the interface of the uninhibited and inhibited systems can be represented by the simple equivalent circuit R (e)(R(ct)Q(dl)).