Room‐temperature measurements of the reversible relaxation of the initial magnetic permeability have been performed in rapidly solidified Fe73.5Cu1Nb3Si13.5B9ribbons at different stages of the transformation from the amorphous to the nanocrystalline phase. The intensity of the relaxation is observed to practically disappear in the nanocrystalline alloy. This result may modify the current views about the structural defects responsible for the magnetic‐permeability relaxation in amorphous ferromagnets.