Rate coefficients of the reaction of hydroxyl (OH) radicals with CHFCl2 (k(1)) and CHF2Cl2(k(2)) over an extended temperature range are reported. Measurements were performed using a laser photolysis-laser-induced fluorescence (LP/LIF) technique under dow flow conditions at a total pressure of 740 +/- 10 Torr. Arrhenius plots of the data exhibited significant curvature and were fitted in the form of k(T) = AT(B) exp(-C/T). A semiempirical fitting approach was used in which A and B were obtained from a transition state theory (TST) calculation and C was determined from a nonlinear least squares fit to the experimental data. The resulting modified Arrhenius expressions were k(1)(T) = (3.13 +/- 0.2) x 10(-18) T-1.93+/-0.01 exp[(-552 +/- 18)/T] cm(3) molecule(-1) s(-1) and k(2)(T) = (3.10 +/- 0.2) x 10(-18) T-1.94+/-0.01 exp[(-1212 +/- 26)/T)] cm(3) molecule(-1) s(-1). This semiempirical fit is shown to be superior to a purely empirical fit to the data. The expressions for k(1) and k(2) are in good agreement with the previous studies between temperatures of 240 and 480 K. Above 480 K, our extended temperature measurements verify previous TST predictions. The experimental results indicate that k(1) is about 5 times as fast as k(2) at 295 K. The difference in room temperature reactivity is consistent with recent BAC-MP4 calculations indicating a nearly 5 kcal/mol difference in C-H bond dissociation energies (BDE).