Polarized Raman spectra were measured from (010) Mg-doped, (100) Si-doped, and (001) unintentionally doped beta-Ga2O3 substrates prepared by either the floating zone growth or edge-defined film-fed growth methods. The A(g) and B-g Raman active modes were perfectly separated in the spectra according to the polarization selection rules. To the best of our knowledge, this is the first experimental observation of a complete set of polarized Raman spectra of beta-Ga2O3. The results are ensured by the high uniformity of crystalline orientation and surface flatness of the present substrates. (C) 2014 Elsevier B.V. All rights reserved.