AbstractIgnition delay times of cyclopentene–oxygen–argon mixtures were measured behind reflected shock waves. Mixtures contained 0.5% or 1% of hydrocarbons for equivalence ratios ranging from 0.5 to 1.5. Reflected shock wave conditions were as follows: temperatures from 1300 to 1700 K and pressures from 7 to 9 atm. When compared with the previous results obtained under similar conditions, it can be observed that the reactivity of cyclopentene is much lower than that of cyclohexene, but very close to that of cyclopentane. A kinetic mechanism recently proposed for the combustion of cyclopentene in a flame has been used to model these results, and a satisfactory agreement is obtained. The main reaction pathways have been derived from the flow rate, simulated temporal profiles of products, and sensitivity analyses. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 40: 25–33, 2008