The report gives results of research to determine the technical feasibility of using metal sulfide for the chemical reduction of NOx to N2. Nineteen different metal sulfides were investigated, using a test gas of pure NO. Although most sulfides resulted in some NO reduction, BaS, CaS, SrS, and FeS were the most promising. Several catalysts reduced the temperature at which the reduction process proceeds by as much as 200 C. A further temperature reduction was obtained by impregnating the sulfide and catalyst on high surface area supports of activated alumina or molecular sieves. The most promising catalysts were NaF, NiC 12, and FeC 12. All combinations of the most promising sulfide and catalysts were tested for NO reduction, using a synthetic flue gas containing 1000 ppm NO and 1% O2. The capacities of the six best were FeS-FeC 12 > SrS-NaF > CaS-NaF > BaS-FeC 12 > FeS-NiCl > CaS-FeC 12, and ranged from 0.0372 to 0.0134 g NO reduced/g initial sulfide present. Capacities of 0.91 and 0.76 g NO/g sulfide were obtained when using 5% CaS (only) impregnated on alumina and molecular sieves, respectively. It was concluded that these sulfides can reduce NO in the presence of O2, but more research is required to establish the economic feasibility.