Perovskite-type catalysts were used for the reduction of nitric oxide with carbon monoxide as an alternative to precious metals, current commercial catalysts, for the neutralization of automobile emission gases. The perovskite-type oxides in the form of ABO₃ and A_1-xA'_xBO₃ were prepared in the laboratory and their structures were confirmed by X-ray diffraction analysis. The activities of catalysts, redox reaction mechanism, and reaction kinetics were studied in a batch recycle-type reactor.