Mordenite-zeolite supported Ca-Cu and Ba-Cu catalysts (Ca-Cu/MOR and Ba-Cu MOR) were successfully fabricated for direct decomposition of both NF3 and N2O gases contained in waste gas stream of (semiconductor) electronics industry. N2O conversion rates of Ca-Cu and Ba-Cu catalysts were 79 and 86%, respectively, at 700°C and 1 atm under space velocity of 5000 h–1. The Ca-Cu catalyst was especially noteworthy in that its capability of converting N2O could be maintained even after its exposure to co-feeding NF3 gas constituent in the waste gas stream. Compositional and surface morphological analyses of the Ca-Cu and Ba-Cu catalysts were made before and after exposure to the waste gas stream to examine any noticeable degradation or change of the catalysts. Unlike Ba-Cu catalyst, SiO2 constituent of the Ca-Cu catalyst was found to remain immune to the NF3-cofeeding waste gas stream, casting a positive prospect for superior and steady N2O decomposition performance via maintenance of its structural integrity.