A series of γ-Al 2O 3-MgO and γ-Al 2O 3-CeO 2 composite oxides with different respective MgO and CeO 2 loadings were prepared successfully via wet impregnation method. The synthesized composite oxides were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy-energy dispersive X-ray analysis (FESEM-EDAX), thermogravimeric analysis (TGA), X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF) and Brunauer-Emmett-Teller (BET) methods. The point of zero charge (PZC) of oxides/mixed oxides was determined by salt addition and potentiometric methods to explore the effects of MgO and CeO 2 contents on the PZC of γ-Al 2O 3. The results showed that, as the MgO loading was increased, PZC of alumina also increased linearly. However, in the case of CeO 2 addition, the change in PZC of γ-Al 2O 3 was not so significant. Moreover, the PZC of these synthesized composite oxides varied between the PZCs of pure oxides of Al 2O 3, MgO, and CeO 2. Further, it was noted that, at lower MgO and CeO 2 loadings, the structure of γ-Al 2O 3 was protected; however, at higher loadings, a change in the structure of γ-Al 2O 3 was observed. XPS results showed that binding energies decreased as MgO and CeO 2 loadings were increased. This decrease in the binding energies of Mg and Ce was attributed to the change in their chemical environment which caused change in the average valence state (oxidation state) of elements. © 2011 American Chemical Society.