Ab initio molecular orbital theory has been used to examine the kinetics and mechanism for the reaction of hydrogen and methyl radicals with methyl formate. From the ab initio results the rate of reaction of hydrogen atoms with methyl formate is found to be significantly faster than the analogous reactions initiated by methyl radicals. Under oxygen rich combustion conditions reactions with H and OH are likely to dominate. Abstraction of the carbonyl hydrogen of methyl formate by H atom is significantly (85%) favored at 298 K. As the temperature increases, however, methyl and carbonyl hydrogen abstraction pathways become more equally probable.