Nanophase Eu2O3 polycrystalline thin films were deposited on Si(100) substrates by nebulization of a 0.01 M solution of europium acetylacetonate (Eu(acac)(3)) in a 50% ethanol/water mixture followed by pulse ultrasonic spray pyrolysis in flowing air. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectrum. The technical conditions leading to optimal performance are identified. An appropriate ratio of pulse time to interval time between pulses is found to be necessary for obtaining homogeneous and uniform nanostructural Eu2O3 thin films.