Cr? Al2O3 Nano composite coatings with various contents of Al2O3 nanoparticles were prepared by electrodeposition inoptimized Cr plating bath containing different concentrations of Al2O3 nanoparticles. Direct current electrocodeposition technique wasused to deposit chromium layers with and without Al2O3 nanoparticles on mild carbon steel. The effects of current density, stirring rateand concentration of nanoparticles in the plating bath were investigated. Energy dispersive analysis technique was used to verify the presence of Al2O3 nanoparticles in the coated layers. Thecorrosion behaviors of coatings were investigated by potentiodynamic polarization and electrochemical impedance spectroscopymethods in 0.05 mol/L HCl, 1 mol/L NaOH and 3.5% NaCl (mass fraction), respectively. Microhardness measurements and pin-on-disctribometer technique were used to investigate the wear behavior of the coatings.