The magnetic properties of annealed Fe(42)Co(42)Nb(7)B(8)Cu(0.5)Ni(0.5), Fe(42)Co(42)Nb(6)B(8)Cu(1)Ni(1) and Fe(42.5)Co(42.5)Nb(6)B(8)Cu(0.5)Ni(0.5) alloys produced by melt spinning have been studied. By simultaneous addition of Cu and Ni elements, the soft magnetic properties of nanocrystalline FeCoNbB alloy with high Curie temperature were greatly improved. The annealed alloys show high Curie temperature of more than 1223 K and excellent soft magnetic properties, i.e., low coercivity of about 30 A/m and high effective permeability of above 5000, and these values are superior to the typical nanocrystalline HITPERM alloys for high temperature applications. (C) 2011 Elsevier B.V. All rights reserved.