The temperature dependence of the rate constant for the F + CH 4 reaction has been determined by a competitive method using the F + D 2 reaction as a reference reaction. Ratios of rate constants k F+CH 4 /k F+D 2 were determined by a discharge-flow-mass spectrometric technique at eight temperatures in the range 184-406 K. These ratios were combined with accurate data for the kinetic isotope effect k F+H 2 /k F+D 2 to obtain ratios of rate constants k F+CH 4 /k F+H 2 , which were then multiplied by recommended values for k F+H 2 to obtain absolute values for k F+CH 4 . The ratios of rate constants k F+CH 4 /k F+D 2 and k F+CH 4 /k F+H 2 and the absolute rate constant k F+CH 4 follow linear Arrhenius dependences over the whole temperature range of the experiments, corresponding to the expressions k F+CH 4 /k F+D 2 ) (1.21 ( 0.04) exp[(420 ( 10)/T], k F+CH 4 /k F+H 2 ) (1.16 ( 0.04) exp [(235 ( 10)/T] and k F+CH 4 ) (1.64 ( 0.05) × 10 -10 exp[-(265 ( 10)/T] cm 3 /(molecule s). The present results of relative and absolute rate constants are compared with previous literature data.