In order to obtain high initial permeability and high Curie temperature, effects of MoO3 and WO3 additives on densification and magnetic properties of the NiCuZn ferrites were investigated. It was confirmed that with proper content, both MoO3 and WO3 additives could promote grain growth obviously and lead to increase of bulk density and initial permeability. Tungsten ions had a stronger trend to incorporate into lattice of the ferrites than the molybdenum ions, so more content of WO3 was necessary to obtain peak bulk density and initial permeability. However, a sharper decrease of Curie temperature was observed for the WO3 added specimens. The MoO3 added specimen got peak initial permeability (which was 2480) With MoO3 of 0.12 wt%, and the Curie temperature could keep at 118 degrees C. The WO3 added specimen got peak initial permeability (which was 2530) with WO3 of 0.16 wt%, and the Curie temperature fell to 110 degrees C. (c) 2007 Elsevier B.V. All rights reserved.