The oxidation of n-propylbenzene was studied experimentally in a jet-stirred reactor at atmospheric pressure over the high temperature range 900-1250 K, and for variable equivalence ratio (0.5 less than or equal to phi less than or equal to 1.5). Concentration profiles of 23 species (reactants, stable intermediates and final products) were measured by probe sampling followed by on-line and off-line GC analyses. For the first time, the oxidation of n-propylbenzene was modeled using a detailed chemical kinetic reaction mechanism (124 species and 985 reactions, most of them reversible) also validated for the oxidation of benzene and toluene. Sensitivity analyses and reaction path analyses, based on species rates of reaction, were used to interpret the results. The routes involved in n-propylbenzene oxidation have been delineated: n-propylbenzene oxidation proceeds via thermal decomposition yielding benzyl and 2-phenyl-1-ethyl, and by H-atom abstraction yielding phenylpropyl radicals. Recombination reactions of benzyl with methyl and H yield ethybenzene and toluene, respectively, whereas the oxidation of these radicals yields benzaldehyde. Phenylpropyl radicals react by beta -scission yielding ethylene, styrene and propene. The isomerization of 1-phenyl-2-propyl to 2-phenyl-1-propyl reduces the importance of propene, formation and increases that of styrene.