Simultaneous catalytic removal of NOx, SOx, and CO under simulated FCC regenerator conditions was investigated over mixed oxide catalysts CuMgAlO (Cu-cat), CeMgAlO (Cc-cat), and CuCeMgAlO (CuCe-cat), which were prepared by coprecipitation and characterized by XRD, XPS, and N-2 adsorption-desorption. At low temperatures (<340 degreesC), the presence of O-2 or H2O enhanced the activity of CuCe-cat for NO and CO conversion but significantly suppressed the activity of Cu-cat and Ce-cat. At high temperature (720 degreesC), the presence of O-2 or H2O had no adverse effect on the NO and CO conversions over these catalysts. However, the presence Of SO2 in the feed deactivated Cu-cat and Ce-cat drastically while no deactivation of CuCe-cat was observed. The enhanced performance of CuCe-cat can be explained by a synergistic effect between copper and cerium ions, which results in the formation of large amounts of Cu+ ions and oxygen vacancies. Thermogravimetric studies show that this catalyst exhibits excellent performance for SOx adsorption in the SO2 + O-2 system and can effectively release the adsorbed SOx in H-2 + Ar atmosphere.