Potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS) and weight loss measurements were used to investigate the inhibitory effect of L-Cysteine Methyl Ester Hydrochloride (L-CMEH) on corrosion of copper in 2M HNO3 solution. The inhibitor showed > 97% inhibition efficiency at 10−3M. EIS results show that the change in the impedance parameters (Rt and Cdl) with concentration of L-Cysteine Methyl Ester Hydrochloride (LCMEH) is indicative of the adsorption of molecules leading to the formation of a protective layer on the surface of copper. Potentiodynamic polarization studies suggested that it is a mixed type inhibitor. The inhibitor studied reduces the corrosion rates. The results obtained from weight loss, polarisation, and impedance measurements are in good agreement.