A chemical kinetic mechanism has been developed to describe the high-temperature oxidation and pyrolysis of n-heptane, iso-octane, and their mixtures. An approach previously developed by this laboratory was used here to partially reduce the mechanism while maintaining a desired level of detailed reaction information. The relevant mechanism involves 107 species undergoing 723 reactions and has been validated against an extensive set of experimental data gathered from the literature that includes shock tube ignition delay measurements, premixed laminar-burning velocities, variable pressure How reactor, and jet-stirred reactor species profiles. The modeled experiments treat dynamic systems with pressures up to 15 atm, temperatures above 950 K, and equivalence ratios less than approximately 2.5. Given the stringent and comprehensive set of experimental conditions against which the model is tested, remarkably good agreement is obtained between experimental and model results. (C) 2007 Wiley Periodicals, Inc.