Spectroscopic ellipsometry has been used to characterize the dielectric functions of bulk Cu2SnSe3 crystals, grown by modified Bridgman technique. Spectral measurements were performed at room temperature over the energy range 1.0 to 4.7 eV. The spectral dependence of the complex dielectric functions, complex refractive index, the absorption coefficient and the normal-incidence reflectivity of Cu2SnSe3 was derived. The structures observed in the measured spectra have been associated with critical points higher than band gap interband transitions. (C) 2012 Elsevier B.V. All rights reserved.