An Al2O3 sample obtained from Seydisehir Eti Aluminyum A.S was treated and characterized for its potential use as a catalyst support. Atomic absorption spectroscopy and flame photometry characterization revealed the presence of 95.52% Al2O3 , 4.44% Na2O, and 0.043% Fe2O3 in the original sample. Both gamma-Al2O3 and alpha-Al2O3 phases were identified in the crystalline structure by X-ray diffraction analysis. However, alpha-Al2O3 was found to be the phase in abundance. The BET surface area of the original sample was found to be 40.85 m(2)/g. The original sample was treated in various concentrations of hydrochloric acid to remove Na2O impurity. The acid concentration was optimized for the Na-2 O removal efficiency and surface area enhancement. The optimum HCl concentration was found to be 1 M. 1 Pt/Al2O3 catalysts prepared from these supports and a reference support (Johnson Matthey gamma-Al2O3) were tested for CO oxidation reactions. Catalysts prepared fromSeydisehir alumina showed reasonable activity for the CO oxidation reaction.