Two groups of TiO2 thin films were deposited onto Corning glass substrates by the RF magnetron sputtering in reactive argon gas containing 20% oxygen and by the sol–gel technique combined with dip coating. The films prepared by RF sputtering were annealed for 15 min at 650 °C with different rates of increase of temperature with the aim to search for the TiO2 anatase phase formation. Besides, with the same aim, a set of the TiO2 films prepared by sol–gel technique was doped with Co in the concentration range from 0 to 8% by weight. Influence of the rate of increase of temperature and Co doping on the anatase phase formation have been observed and estimated by x-ray diffraction and Raman scattering. Structure deformation induced by rapid heating and Co doping is considered as the main reason affecting the anatase phase formation in TiO2 thin films. Copyright © 2005 John Wiley & Sons, Ltd.