A method for determination of Young's modulus (E) of thin porous films using data obtained by ellipsometric porosimetry (EP) is reported. The calculated E values are in good agreement with data obtained by nondestructive methods like surface acoustic wave spectroscopy (SAWS) and Brillouin light scattering (BLS). These three methods (SAWS, BLS, and EP) use different physical ideas for determination of Young's modulus. Good agreement among these data suggests that the obtained data are more realistic than data obtained by nanoindentation that gives remarkably larger E values. (C) 2002 The Electrochemical Society.