The kinetics of chemical transformation in N2O-H-2-O-2-Ar mixtures has been studied in the temperature range from 1000 to 2700 K and at pressures from 0.1 to 10 atm. A shock-tube experiment has been used to obtain data on the times of ignition delay in mixtures weakly diluted with inert gas (50 to 90% Ar). Based on the results, a mechanism to describe the kinetics in the system under study has been suggested. The values of rate constants of some chemical reactions involving N2O, NO, and OH have been specified. (c) 2007 The Combustion Institute. Published by Elsevier Inc. All rights reserved.