The corrosion inhibition effect of Isatin (1-H-indol-2,3-dione)-p-toluidine (HIPT) Schiff base as an inhibitor on carbon steel in 1M HCl was studied by weight loss, potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) techniques. Weight loss was studied for different immersion time at different concentrations (50-250 ppm) of inhibitor in temperature range 25°C-45°C. The results showed increase in inhibition efficiency, surface coverage but decrease in corrosion rate with the successive increase in the concentration of the inhibitor. HIPT showed maximum inhibition efficiency of 87.94% in 250 ppm concentration. Adsorption of this inhibitor found to obey Langmuir adsorption isotherm. Thermodynamic data indicates the adsorption process to be physical in nature. Polarization data depict inhibitor as mixed type in nature. EIS data revealed the dependence of corrosion process on charge transfer process.