The corrosion inhibition characteristics of Sulfamerazine (SFM) on mild steel immersed in 1 M HCl solution were investigated. Weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamicpolarisation (PDP) was used as basis for studying the corrosion inhibition behavior of the compound. The results show that the inhibition efficiency increase with increase in SFM concentration in the acidic solutions but decreases with increase in temperature. Specifically. Langmuir isotherm best fits the data obtained suggesting chemical and physical adsorption as the adsorption mechanism between the SFM and the mild steel substrate. Polarization curves indicate that compound is mixed-type inhibitor, affecting both cathodic and anodic corrosion currents. The morphological study indicated adsorption of inhibitor molecules on the surface of the mild steel. The density functional theory (DFT) was employed for theoretical calculations. The results obtained from experimental measurements and those from theoretical calculations are in good agreement.