Amorphous Fe‐B ribbons with 72‐88a/oFe were prepared by melt‐spinning. The inception of crystallization and the growth of crystals was determined by differential scanning calorimetry. The activation energy, &Dgr;E, and the pre‐exponential constant,A, for both the inception of crystallization and the peak in the crystallization exotherm are independent of composition from 72‐82a/oFe. &Dgr;EandAsteadily decline as the Fe content is increased from 82 to 88a/oFe. The concurrence of the &Dgr;EandAvalues for the inception of crystallization and for the peak in the crystallization exotherm suggests that the same diffusion mechanism is controlling the kinetics in both periods. This compositional dependence of constants in the Arrhenius relation is attributed to decreased filling of holes by B in the Bernal‐like structure as the Fe content increases.