Although the reactivity and structures of hydrocarbon molecules are well known from a high number of experimental and theoretical studies, the correlation between kinetic parameters and experimental cetane number (CN) data on these systems remains unstudied. Quantum mechanical calculations are carried out with B3LYP/6-311G(d,p) and BH&HLYP/6-311G(d,p) methods in order to predict initiation step rate constants for a series of five combustion reactions involving molecules such as ethane, propane, butane, pentane and n-heptane. This work reinforces the argument that the molecular structures of the activated complexes involved in the auto-ignition processes are related to the experimental CN data [see, J. Mol. Struct. Theochem 621 (2003) 293 and J. Mol. Struct. Theochem 631 (2003) 241]. For the linear hydrocarbon molecules studied here, two regression equations are proposed from which computed-cetane-number data are provided. An excellent correlation between calculated rate constants and experimental CN data for these reactions is shown. This correlation is better with rate constants calculated with the BH&HLYP/6-311G(d,p) method than the B3LYP/6-311G(d,p) one.