Nanocrystaltine La0.9Sr0.1Al0.85Co0.05Mg0.1O3 oxide powder was synthesized by a citrate-nitrate auto-ignition process and characterized by thermal analysis, X-ray diffraction, and impedance spectroscopy measurements. Nanocrystalline (50-100 nm) powder with perovskite structure could be produced at 900 degrees C by this process. The powder could be sintered to a density more than 96% of the theoretical density at 1550 degrees C. Impedance measurements on the sintered samples unequivocally established the potential of this process in developing nanostructured lanthanum aluminate-based oxides. The sintered La0.9Sr0.1Al0.85Co0.05Mg0.1O3 sample exhibited a conductivity of 2.40 x 10(-2) S/cm in air at 1000 degrees C compared with 4.9 x 10(-3) S/cm exhibited by La0.9Sr0.1Al0.85Mg0.15O3.