The octahedral nickel ferrite powders were prepared from alpha-FeOOH and amorphous Ni(OH)(2) in high alkali medium via a hydrothermal process. The uniformity of the products can be controlled by simply adjusting the concentration of the NaOH solution. The products were characterized by XRD, TEM, IR and vibrating sample magnetometer (VSM) techniques. The effects of the precursors and reaction conditions on the crystallization of the products are also discussed. (C) 2003 Elsevier Science B.V. All rights reserved.