Nanocrystalline NiO has been successfully synthesized via a low temperature molten composite hydroxide route using nickel chloride hydrate as nickel source. The as-obtained oxide nanocrystals were characterized by X-ray powder diffraction and transmission electronic microscopy. It is found that the ratio of reagent to molten solvent has a great influence on the quality of the products. The effect of temperature and time was also investigated. The present route may have a good prospect to prepare many functional nanomaterials. (C) 2007 Elsevier Ltd. All fights reserved.