The rate constants for the reactions of OH radicals with trifluoromethyl trifluorovinyl ether (CF3OCF = CF2) and hexafluoropropene (CF3CF = CF2) have been measured over the temperature range 250-430 K. Kinetic measurements have been carried out using the flash photolysis and laser photolysis methods combined, respectively, with the laser-induced fluorescence technique. The Arrhenius rate constants have been determined as k(CF3OCF=CF2)=1.01(-0.04)(+0.04) x 10(-12) exp[(320 +/- 10)/T], and k(CF3CF = CF2) = 8.74(-0.33)(+0.34) x 10(-13) exp[(260 +/- 10)/T] cm(3) molecule(-1) s(-1).