Polycrystalline La2O3 thin films with monoclinic structure were deposited on Si(100) substrates by nebulization of a 0.01-M solution of La(acac)(3) in a 50% ethanol/water mixture followed by pyrolysis in flowing air. The films were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Crystalline size depends on the ratio of the spray pulse time and the interval time between pulses was found to increase with decreasing ratio.