The effect of vacuum deposition temperature on the structure and electrooptical properties of polyaniline (PAN) thin films has been studied. In ellipsometry investigations, it has been found that films deposited at 300-400 degrees C at a pressure of 1 x 10(-6) Torr with 20-40 nm thickness possess an optical anisotropy. The films obtained at a deposition temperature of 450 degrees C are characterized by a high electrochemical and electrooptical activity. They have an improved morphology and oxidation-reduction stability as compared to those of the films formed by the electrochemical polymerization method.