Ten to twenty-three nanometers of LaNiO3 nanocrystals were prepared by glycine combustion method using nickel nitrate and lanthanum nitrate as raw materials, glycine as gelating agent and fuel. The preparation process was monitored by thermogravimetric analysis and differential thermal analysis (TG-DTA); the final products were characterized by X-ray diffraction (XRD), electron diffraction (ED), high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The effect of thermal treatment temperature on crystal size of the nanocrystals was studied and the activation energy of LaNiO3 nanocrystals formation during calcinations was calculated to be 41.9 kJ/mol. Moreover, the interplanar distances of d(110) and d(101) measured from the TEM images were 0.272 and 0.363 nm, respectively, coinciding with the theoretical values. (C) 2005 Elsevier Ltd. All rights reserved.