The inhibiting effect of Esomeprazole magnesium trihydrate drug on the corrosion of mild steel (MS) in 1 M HCl was performed by chemical tests (weight loss (WL)) and electrochemical methods (Tafel polarization (TP), electrochemical frequency modulation (EFM) and AC impedance spectroscopy (EIS)). The adsorption isotherm of Esomeprazole Mg Trihydrate drug on the MS surface was found to follow Temkin adsorption isotherm. Some thermodynamic parameters were computed and discussed. The obtained data showed that the inhibition efficiency (IE) rises with increasing the dose of the Esomeprazole Mg Trihydrate and with raising the temperature. The morphology of MS surface was analyzed by using scanning electron microscope (SEM) and atomic force microscopy (AFM) techniques. Fourier transforms infrared spectroscopy (FTIR). All test methods gave corresponding results.