The thermal decomposition of N2O, N2O .88N2, and N2O AIR was investigated in a flowing system. These studies were conducted at 11.2 atmospheres over the temperature range from 772 deg K to 1233 deg K, and total flow rates from 1.0 to 3.76 literssec. Total residence times in the heated section range from approximately .1 to 2.5 sec. A maximum reacted gas temperature of 1588 deg K was obtained. Chromatographic analysis of the products of decomposition showed that the maximum nitrogen dioxide yield was 4.44 for the N2O AIR mixture, 5.09 for the N20 .88N2, mixture, 7.55 for the pure N2O decomposition. Spectrographic observations of the emitted radiation from the decomposition reactions showed the presence of nitrogen dioxide in the reaction. Nitrogen dioxide absorption bands were found. There was no evidence of any discrete bands in emission.