The effect of Ru-loading on the performance of Ru-NaZSM-5 catalysts prepared by ion exchange (extent of ruthenium exchange : 20-100%) in the decomposition of nitrous oxide was studied in the temperature range of 40-700 degrees C. The turnover frequency (TOF) for nitrous oxide decomposition (number of nitrous oxide molecules converted per ruthenium site per unit time) increased significantly with decreasing Ru-loading. Although lower Ru-loading resulted in higher TOF and lower apparent activation energy for nitrous oxide decomposition, this occurred at the expense of stronger inhibition by oxygen. Therefore, to obtain catalysts that remain active in the presence of excess oxygen, high Ru-loaded catalysts (close to 100% of exchange) are needed; whereas in the absence of oxygen, low Ru-loadings (close to 20% of exchange) are preferred. The high TOF observed in Ru-NaZSMS-20 was attributed to the interaction between ruthenium and sodium cations.