Pt–Ru catalysts of various compositions, between 0 and 100at.% of Ru, were deposited onto N-doped multi-walled carbon nanotubes (N-CNTs) by atomic layer deposition (ALD) at 250°C. The Pt and Ru precursors were trimethyl(methylcyclopentadienyl)platinum (MeCpPtMe3) and bis(ethylcyclopentadienyl)ruthenium (Ru(EtCp)2), respectively. O2 was used as the reactant in both processes. The composition of the catalysts was easily tuned by varying the Pt-to-Ru ALD cycle ratio. The catalysts were tested toward the CO oxidation and methanol oxidation reaction (MOR) in a three-electrode electrochemical set-up. For the compositions investigated, the catalysts with a Ru content of 29at.% exhibited highest catalytic activity.