Platinum nanoparticles/graphitic carbon nanotubes (GCNTs) nanocomposites are fabricated with electrostatic self-assembly technology. Pt precursors are uniformly distributed on poly(diallyldimethylammonium chloride)-functionalized GCNTs surface (PDDA-GCNTs) via the electrostatic interaction and then in situ reduced to Pt nanoparticles in ethylene glycol, where PDDA is not only used as the wrapping polymer for GCNTs to preserve the integrity and the electronic structure of GCNTs, but also facilitates the uniform distribution of Pt nanoparticles on the surface of GCNTs. X-ray diffraction patterns and transmission electron microscope images reveal that Pt nanoparticles with an average size of similar to 2.7 nm are uniformly dispersed on highly graphitized GCNTs. Significant enhancement in the electrocatalytic activity on Pt/PDDA-GCNTs catalyst towards oxygen reduction reaction (ORR) has been demonstrated. In addition, this catalyst also shows enhanced electrochemical durability due to the high graphitization degree of GCNTs. This provides a facile and eco-friendly approach to large-scale production of high performance fuel cell eletrocatalysts. (C) 2010 Elsevier B.V. All rights reserved.