A novel approach to the synthesis of mono-dispersed platinum nanoparticles (Pt NPs) on multiwalled carbon nanotubes (MWNTs) has been proposed. With this method, we successfully assembled mono-dispersed Pt NPs on MWNTs. The method involved the in situ high-temperature decomposition of the precursor, platinum (II) acetylacetonate (Pt(acac)2), in liquid polyols. We used X-ray diffraction, scanning electron microscopy, and transmission electron microscopy to characterize the resulting MWNTs covered with Pt NPs (Pt@MWNTs). We found that the size of the Pt NPs and the coverage density on MWNTs could be tuned easily by changing the reaction temperature and the initial mass ratio of Pt(acac)2 to MWNTs. Electrocatalytic measurements showed that the Pt@MWNTs had excellent catalytic activities in the electrooxidation of methanol and in the oxygen reduction reaction. These Pt@MWNTs have potential applications in fuel cells and biosensors. (C) 2014 Elsevier B.V. All rights reserved.