A method named refluxing method has been shown for preparing nanocrystalline Ni-Zn ferrite powders with a narrow particle size distribution. The variation of the samples refluxed for different tildes has been investigated by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) and a recipe for the preparation of nanosized ferrite has been developed. Single-phase Ni-Zn ferrite has been found to form at a temperature of about 107 degrees C and with a calcination time of 6 h. The average diameter of the powders as-prepared is about 10 nm. (c) 2005 Elsevier B.V. All rights reserved.