The electronic-band structure parameters of chromium-doped indium oxide films with crystalline structural transition were determined by fitting the dielectric functions of Drude and Adachi's model to near-normal reflectance spectra. The evaluated optical bandgap shows a maximum at an intermediate state and decreases respectively toward highly and less ideally crystallized states. We explain this phenomenon by combining the effect of intrinsic bandgap narrowing with the Burstein-Moss shift, both due to the crystalline structural transition. This work provides important insights into electronic-band structures of less ideally structured materials. (C) 2011 Elsevier B.V. All rights reserved.