Acicular NiZn-ferrite powder particles have been prepared from goethite-derived acicular Fe2O3 and spherical constituent oxides in the presence of molten chloride or sulphate. The morphology of NiZn-ferrite particles has been studied with reference to the effect of chemical species of molten salts, ferrite composition and particle size of constituent divalent oxides. Hence the best preparation conditions for acicular NiZn-ferrite powder with homogeneous composition have been determined; a mixture of acicular Fe2O3 and submicron constituent oxides is heated at 900° C in an amount of potassium chloride with four times the weight of ferrite. Electron diffraction analysis shows that the particle axes of acicular Fe2O3 and NiZn-ferrite are parallel to [¯1 1 0 0]haematite and [¯1 0 1]ferrite and that a topotactic relation is retained.