The gas-phase oxidation of methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) has been experimentally studied using a jet-stirred reactor between 750 and 1150 K (pressure of 10 atm, equivalence ratios from 0.5 to 2 with an important dilution in nitrogen). These experiments have been modeled using a kinetic mechanism automatically generated by EXGAS, the system developed in Nancy. The modeling of the oxidation of several mixtures of these ethers with n-heptane has also been performed in an extended temperature range, between 580 and 1100 K, covering the regions of cool flames and a negative temperature coefficient. The agreement between the computed and the experimental values is mostly good, both for conversions and for the distribution of major products, except for the lowest temperatures, where catalytic effects should be taken into account. The decrease of reactivity due to the addition of MTBE or ETBE to n-heptane at low temperatures is well predicted by the model. (C) 2000 by The Combustion Institute.