The crystallization kinetics of Fe-based amorphous alloys was investigated by differential thermal analysis (DTA) and differential scanning calorimetry (DSC). Rather high values of activation energies were explained as a result of simultaneously correlated displacements of groups of atoms during the course of crystallization and allowed the correlation of amorphous alloys regarding their different composition. Connections between the temperatures, activation energies and thermodynamic driving forces were considered. Special attention was paid to the formation of nanocrystalline structures (Finemet).