Nano-crystalline Zirconia (ZrO2) coatings of different thicknesses were grown on pre-oxidized stainless steel (SS) by hydrothermal method in a static autoclave. Hydrothermal deposition process was repeated multiple times in order to enhance the coating thickness. Four cycles of the deposition process led to the development of similar to 1 mu m thick ZrO2 coating on the pre-oxidized SS surface. Corrosion resistance properties of the pre-oxidized SS and ZrO2 coated samples were studied by potentiodynamic polarization (PDP) technique and electrochemical impedance spectroscopy (EIS). First round of ZrO2 deposition resulted in similar to 200 nm thick, continuous but porous ZrO2 coating. Porosity in the coating reduced drastically after the second round of deposition. PDP and EIS analyses showed that the corrosion resistance of SS specimens improved with coating thickness. Growth of both tetragonal and monoclinic phases of ZrO2 in the coating was observed after second round of deposition process. Intrinsic stresses due to change in the phases were accommodated at the grain boundaries when grain size was small (similar to 200 nm), but it deteriorated the coating's corrosion resistance properties when the grain grew to the size of around 500-1000 nm.