Nanocrystaltine, single phase, and highly homogeneous La0.84Sr0.16MnO3 (LSM) powder was prepared by a unique spray-pyrolysis process for solid oxide fuel cell applications. Atomization of a citrate-nitrate precursor solution consisting of La3+, Sr2+, and Mn2+ ions in the molar ratio 0.84:0.16:1.0, which can initiate a controlled exothermic anionic oxidation-reduction reaction leading to a self-propagating auto-ignition (self-ignition) reaction within individual droplets led to the conversion of the precursor to their corresponding single-phase LSM powder. Characterization of the as-sprayed and calcined products by X-ray powder diffraction, thermal analysis, and microstructural analysis confirmed the formation of nanocrystal-line single-phase LSM powder by this process.