The present study investigates the influence of grain refinement on the electrochemical response of Fe-18.5% Cr ferritic stainless steel in 0.01 M NaOH solution. To investigate the electrochemical behavior of material, the open circuit potential measurement, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry analysis was carried out. OCP analysis demonstrated that the passive film formed on coarse-grained sample is more stable than fine-grained one. ESI measurements also indicated that grain refinement reduces the thickness of the passive film and degrades the corrosion resistance. Also, the potentiodynamic polarization measurements showed that grain refinement reduces the corrosion resistance of Fe-18.5 Cr ferritic stainless steel in the NaOH solution.