The kinetics of CF3CFHO radical reactions was studied at 20 and 35 Torr and from 259 to 297 K by flash photolysis with time-resolved mass spectrometry. The CF3CFHO2 radical was generated by flash photolysis of Cl-2 in the presence of CF3CFH2 and O-2, and CF3CFHO was formed by the reaction of CF3CFHO2 with Cl and by the peroxy radical self-reaction. The rate coefficient ratio for (1) CF3CFHO + O-2 --> CF3C(O)F + HO2 and (2) CF3CFHO --> HC(O)F + CF3 was determined by observing the formation of HC(O)F as a function of the partial pressure of O-2. At 20 Torr, k(1)/k(2) = (2.4 +/- 0.8) x 10(-25) e((4248 +/- 550)/T) cm(3) molecule(-1), and at 35 Torr, k(1)/k(2) = (9.1 +/- 3.3) x 10(-26) e((4370 +/- 500)/T) cm(3) Molecule(-1). Ab initio molecular orbital calculations for optimized geometries, vibrational frequencies, and total energies of CF3CFHO, the reaction products, and the C-C bond-breaking transition state were made. Energies were calculated by the G2 and G2(MP2) methods. An RRKM model for reaction 2 was based on geometries and energies from the ab initio calculations. RRKM calculated values of k(2) were combined with the experimentally determined k(1)/k(2) to estimate k(1). Comparisons were made with estimates made with two other RRKM models (Schneider, W. F.; Wallington, T. J.; Barker, J. R.; Stahlberg, E. A. Ber. Bunsen-Ges. Phys. Chem. 1998, 102, 1850; Somnitz, H.; Zellner, R. Phys. Chem. Chem. Phys. 2001, 3, 2352). The ab initio calculations predict the 298 K enthalpy of formation of CF3CFHO to be -203.0 kcal mol(-1) (G2MP2) and -203.4 kcal mol(-1) (G2).