The kinetics of the gas-phase decomposition of methyl trifluoroacetate and 2,2,2-trifluoroethyl trifluoroacetate, two esters without hydrogen atoms, have been investigated, and a comparative study was carried out on methyl acetate. All these compounds are thermally much more stable than fluorinated esters with hydrogens, decomposing at temperatures some 150°C above the latter by a completely different mechanism involving partly heterogeneous radical chains. The marked difference in behavior between the two types of fluorinated ester confirms that none of them decomposes by hydrogen fluoride elimination, but that those with hydrogen atoms follow the normal ester decomposition route. The fluorinated esters examined here decompose in a manner generally similar to methyl acetate, but the presence of fluorine in the molecule brings about an extreme sensitivity to surface conditions.