Flow reactors are commonly employed in investigations of the pyrolysis and oxidation chemistry of fuels. Typical flow reactors use either electrical heaters or vitiation heaters to provide the energy to preheat the reactants to the desired experimental conditions. The present study seeks to determine the impact of vitiation on flow reactor studies of fuel combustion chemistry by conducting both fuel pyrolysis and oxidation experiments in a flow reactor in which either an electrical heater or a vitiation heater is used as the energy source. Other than the heater all other aspects of the flow reactor are identical. Two fuels relevant to air-breathing propulsion systems were investigated - Jet A and JP-10. Profiles of the stable reaction products were measured using gas chromatography for a temperature of 1030 K at a pressure of 1 atmosphere, with residence times between 30 ms and 70 ms. The primary hydrocarbon products for Jet A pyrolysis and oxidation were C2H4, C3H6, CH4, C4H8, C6H6 and C7H8. For JP-10, in addition to these species, cyclopentene (C5H8) and cyclopentadiene (C5H6) were measured. Under the conditions investigated, vitiation decreases the reaction times scales for both pyrolysis and oxidation. However, the product yields at a fixed fuel conversion were nearly identical for both the vitiated and non-vitiated experiments. Current kinetic models for Jet A and JP-10 pyrolysis and oxidation adequately captured the observed effects of vitiation on the stable species profiles. (C) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.