Time-resolved, laser-induced fluorescence (LIF) measurements have been carried out on the kinetics of CN (ν=0) and CN (ν=1) with H 2 and D 2 between 295 and 768 K. The rate constants for reaction of CN (ν=0) with H 2 and D 2 are fitted well by the modified Arrhenius expressions: (2.4±0.7)×10 −12( T/298) 1.6±0.2exp[−(1340±90)/ T] and (7.9±1.5)×10 −13 × ( T/298) 2.2±0.1 exp[− (1330±60)/ T] cm 3 molecule −1 s −1 (errors quoted are one standard deviation). The rate constants for CN (ν=1) with H 2 and D 2 are, within experimental error, the same, except for D 2 at low temperatures when the rate of removal of CN(ν=1) is slightly less than that of CN(ν=0). The experimental results are compared with the results of conventional transition state theory calculations based on ab initio information about the transition state. With the barrier height scaled to reproduce the experimental rate constant for CN+H 2 at 295 K, the kinetic isotope effect and the variation of both rate constants with temperature are predicted quite well.