The CO + NO reaction on Pd(1 1 1) has been studied at pressures up to 240 mbar using in situ polarization modulation infrared reflection- absorption spectroscopy (PM-IRAS), which simultaneously provides information on the in situ adsorption behavior as well as the reaction kinetics via gas-phase infrared absorption. Under reaction conditions (> 500 K) and at pressure ratios P-CO/P-NO greater than or equal to 1.5, besides CO and NO, isocyanate is adsorbed on the surface as evidenced by isotope experiments. The kinetics of the CO + NO reaction to form CO2, N2O, and N-2 was followed by monitoring the evolution of gas-phase CO2 and N2O. Above 550 K, a substantial increase in activity was observed. Kinetic measurements between 590 and 650 K showed an increase in the N2O selectivity as a result of temperature-dependent changes of the ratio [NO](a)/[CO](a). Within this temperature range and on the basis of the CO2 yields, the apparent activation energy of the reaction was determined to be 54 +/- 21 kJ/mol.