Epitaxial thin films of bismuth ferrite, BiFeO(3), were deposited by pulsed laser deposition (PLD) on SrTiO(3) (100), Nb-doped SrTiO(3) (100) and DyScO(3) (110) substrates. Ellipsometric spectra are obtained in the energy range 0.73-9.5 eV by combining Variable Angle Spectroscopic Ellipsometry (VASE) and vacuum ultraviolet (VUV) ellipsometry with synchrotron radiation. The optical constants of BiFeO(3) films were determined by analysing the ellipsometric spectra with a model that describes the optical response of a system consisting of air, film and substrate. The shift towards higher energies of the refractive index and extinction coefficient of the film deposited onto Nb-doped SrTiO(3) as compared with that deposited onto DyScO(3) was attributed to a more compressive in-plane epitaxial strain. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim