The kinetics of the reactions of OH and OD with acetone and acetone-d 6 were studied from 2–5Torr and 258–402K using a discharge flow system with laser induced fluorescence or resonance fluorescence detection of the OH radical. The rate constants at 300K for the reaction of OH with acetone and acetone-d 6 were (1.73±0.06)×10 −13 and (3.36±0.32)×10 −14 cm 3 molecule −1 s −1 , respectively. The rate constants at 300K for the reaction of OD with acetone and acetone-d 6 were (2.87±0.22)×10 −13 and (3.69±0.12)×10 −14 cm 3 molecule −1 s −1 , respectively. Above room temperature, the temperature dependence of the rate constants for the OH+acetone and acetone-d 6 display Arrhenius behavior and are described by the equations k H (T)=(3.92±0.81)×10 −12 exp(−938±70/T) and k D (T)=(8.19±1.45)×10 −12 exp(−1647±58/T) cm 3 molecule −1 s −1 for acetone and acetone-d 6 , respectively. Measurements of k H and k D below room temperature begin to display non-Arrhenius behavior, consistent with previous measurements at higher pressures. Theoretical calculations of the kinetic isotope effect as a function of temperature are in good agreement with the experimental measurements using a hydrogen abstraction mechanism that proceeds through a hydrogen-bonded complex.