This work focuses on the investigation of the photocatalytic activity of the TiO2thin films (either modi-fied or unmodified by noble metal) and on its stability during 16 months after deposition. RF dischargewas used to deposit the TiO2thin films by PECVD from the mixture of titanium isopropoxide (TTIP)vapors and oxygen. The surface of TiO2films was subsequently modified by Ag or Pt by means of mag-netron sputtering. Several analytical methods were used to characterize the thin films properties. XPSwas used to investigate the chemical composition of the surface, SEM to study the surface morphology.The photocatalytic activity was expressed in terms of photocatalytic efficiency and it was determinedby decomposition of the organic dye Acid orange 7 (AO7). The results show that the enhancement ofthe photocatalytic efficiency achieved by the modification by Ag or Pt decreases with time, but it is stillseveral times higher after 16 months aging than in case of unmodified TiO2 layers.