Quantum mechanical and Rice-Ramsperger-Kassel-Marcus calculations are carried out to study the thermal unimolecular decomposition of CF2XO radicals (X = Br, Cl). Two kinds of dissociation mechanisms are possible, carbon-halogen bond scission and intramolecular three-center XF elimination. It should be noted that the three-center direct XF elimination has only been able to be characterized at the B3LYP level. X-atom elimination is shown to be the dominant reaction pathway, whereas C-F bond scission and XF elimination have been found to exhibit high energy barriers. On the basis of the ab initio data, energy-specific rate constants k(E) and thermal rate constants k(T,P) are evaluated using master equation numerical analysis.