This paper presents results of investigations of nitrous oxide decomposition in the temperature range (1100 to 1600 K). Experiments were carried out at atmospheric pressure in a quartz flow reactor externally heated in an electrical furnace. Mixtures of N2O/Ar, N2O/H2O/Ar and N2O/CO2/Ar of various reactants contents were used during experiments. Some experiments with very lean CH4/ air mixtures were also performed. Based on these experiments and modelling of a one-dimensional flow reactor, the kinetic parameters of the reaction N2O + M double left right arrow N-2 + O + M for Ar, H2O and CO2 as M were determined. The relative efficiencies compared to Ar were found to be 3.0 for CO2 and 10.0 for H2O, that for CO2 confirms the finding by Glarborg et al. (1994) while for H2O is 20% lower.