Current work presents results of studies on structural and optical properties of the TiO2 thin films prepared by reactive magnetron sputtering. Oxide thin films were deposited from metallic targets using oxygen gas only instead of usually used mixture of Ar-O2. Additionally, an increased amplitude of unipolar pulses powering the magnetron has been applied. It is shown that all prepared coatings were stoichiometric and by changing only the discharge voltage it is possible to influence the resulting structural phase and optical properties of prepared thin films. Depending on conditions of magnetron powering, TiO2 thin films had either the anatase structure with refraction index n = 2.1 (λ = 500 nm) or a high temperature stable rutile structure with n = 2.52 (λ = 500 nm).