This study shows the preparation of a TiO_2 coated Pt/C(TiO_2/Pt/C) by atomic layer deposition(ALD),and the examination of the possibility for TiO_2/Pt/C to be used as a durable cathode catalyst in polymer electrolyte fuel cells(PEFCs). Cyclic voltammetry results revealed that TiO_2/Pt/C catalyst which has 2 nm protective layer showed similar activity for the oxygen reduction reaction compared to Pt/C catalysts and they also had good durability. TiO_2/Pt/C prepared by 10 ALD cycles degraded 70% after 2000 Accelerated degradation test, while Pt/C corroded 92% in the same conditions. TiO_2 ultrathin layer by ALD is able to achieve a good balance between the durability and activity, leading to TiO_2/Pt/C as a promising cathode catalyst for PEFCs. The mechanism of the TiO_2 protective layer used to prevent the degradation of Pt/C is discussed. This study shows the preparation of a TiO 2 coated Pt / C (TiO 2 / Pt / C) by atomic layer deposition (ALD), and the examination of the possibility for TiO 2 / Pt / C to be used as a durable cathode catalyst in polymer electrolyte fuel cells (PEFCs). Cyclic voltammetry results showed that TiO 2 / Pt / C catalyst which has 2 nm protective layer showed similar activity for the oxygen reduction reaction compared to Pt / C catalysts and they also had good durability. TiO 2 / Pt / C prepared by 10 ALD cycles degraded 70% after 2000 Accelerated degradation test, while Pt / C corroded 92% in the same conditions. TiO 2 ultrathin layer by ALD able to achieve a good balance between the durability and activity, leading to TiO 2 / Pt / C as a promising cathode catalyst for PEFCs. The mechanism of the TiO 2 protective layer used to prevent the degradation of Pt / C is discussed.