The decomposition of N2O either alone or with several reducing agents (CH4, CO, NO and D-2) was followed by temperature-programmed desorption of surface species formed during the reactions. TPD products formed in these "primary" reactions were compared with the TPD products after "secondary" reactions of the same set of reducing agents with the surface species formed during the primary reactions. Changes in TPD products after reactions measured under various conditions were analyzed in detail. These experiments provided a background for studies of the nature and reactivity of surface species formed during N2O reactions over Fe-ferrierite. The relevance of these experimental results to the mechanism of the N2O elimination is discussed.