Titanium-oxide-based films were prepared by reactive dc magnetron sputtering in Ar+O2+CF4. Pronounced electrochromism was found in LiClO4+propylene carbonate. The maximum coloration efficiency was 37 cm2/C at a wavelength of ∼0.7 μm. Polaron hopping is believed to cause the absorption. Coloration/bleaching was performed for up to 2×104 cycles without apparent degradation.