A modified solution combustion approach was used in the preparation of nanosize LaAlO3 (similar to 23.6 nm) using mixture of citric acid and oxalic acid as fuels with corresponding metal nitrates. The synthesized and calcined powders were characterized by Fourier transform infra red spectrometry (FTIR), Differential thermal analysis-Thermogravimetry analysis (DTA-TGA), X-ray diffractometry (XRD) and Transmission electron microscopy (TEM). The FTIR spectra show the lower frequency bands at 656 and 442 cm(-1) corresponds to metal-oxygen bonds (possible La-O and Al-O stretching frequencies) vibrations for the perovskite structure compound. DTA confirms the formation temperature of LaAlO3 varies between 830-835 C. XRD results show that mixture of fuels ratio is influential on the crystallite size of the resultant powders. The average particle size of LaAlO3-1 as determined from TEM was about 41 nm, whereas for LaAlO3-2 and LaAlO3-3 samples, particles are seriously aggregated. (C) 2009 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.