Crystallization behavior and magnetic properties of rapidly solidified Fe73.5Nb3Si13.5B9 alloys were studied with 1 at .% Cu or Mn or Pt as the fifth alloying element. Crystallization behavior was investigated by electrical resistivity and differential scanning calorimetry techniques. Addition of Mn or Pt enhanced the temperature coefficient of resistivity. A two stage crystallization process was observed in Cu-containing alloys whereas the Mn- and Pt-containing alloys exhibited three-stage processes. A broad exothermic maximum with the onset at 808 K, which is characteristic of the formation of Fe3Si nanoparticles was observed only in Cu-containing samples. The formation of various intermetallic phases along with the Fe3Si nanoparticles in annealed Mn and Pt systems made these two alloys magnetically inferior compared to the Cu-containing alloy. © 2001 Elsevier Science B.V. All rights reserved.