Reaction F-2+ C2H4 -> F+ C2H3F (1) has been studied using a discharge flow reactor combined with an electron impact ionization mass spectrometer. The reaction rate constant was determined either from kinetics of the reaction product, F-atom, formation or from the kinetics of F-2 consumption in excess of C2H4:k(1)=(7.94 +/- 2.06) x10(-12) exp(-(3867 +/- 120)/T) cm(3) molecule(-1) s(-1) at T= 297-833 K. The reaction activation energy, 7.7 +/- 0.3 kcal mol(-1), is consistent with current theoretical prediction for the reaction barrier height and seems to solve the long-standing problem of the divergence between theory and experiment.