Using high level model chemistries the C-C and C-H bond dissociation energies for methyl butanoate molecule (MB) were estimated using the Gaussian 03 program at the CBS-QB3 level of calculations. This consequently located the weaker bonds more likely to break. Thermal decomposition of MB over the temperatures 500 to 2000 K was theoretically studied and the rate constants for these channels were calculated. Crucial reactions in combustion, among which there are reactions of the fuel molecule with flame reactive radicals OH and CH3, were studied and the barrier heights for reactions including different hydrogen atoms transferring to the radicals were evaluated at the B3LYP/6-31+G(d, p) level of theory. The rate constants for these reactions are calculated over the temperatures 500 to 2000 K using the same level.