FT-IR spectroscopy and mass spectrometry have been used to study the adsorption and decomposition of nitrous oxide on zirconia. It was determined that zirconia cations in the 4+ oxidation state are the site for molecular adsorption of N2O, whereas Zr3+ sites are active toward dissociative adsorption of N2O at temperatures as low as 25 degrees C. Catalytic decomposition of N2O on ZrO2 occurs at temperatures above 350 degrees C and follows first-order reaction kinetics. Experiments utilizing isotopic labeling in conjunction with mass spectrometry were done to elucidate the details of the reaction mechanism. Based on the results presented here, a mechanism for N2O decomposition on ZrO2 is proposed.