This work is focused on the electro-crystallization of Pt nanostructured particles on activated multiwall carbon nanotubes (MWCNTs) containing substrate to produce polymer electrolyte fuel cells gas diffusion electrodes. An activation procedure to enhance the reactivity of multiwall carbon nanotubes surface toward electro-deposition has been studied and optimized. Electrochemical single-and multi-pulsed galvanostatic deposition has been applied defining the best operational parameters leading to a highly nanostructured electrode morphology. Electrochemical measurements (in half-cell configuration) and polarization curves in 5 cm2 single-cell station have been carried out together with morphological analysis by means of scanning electron microscopy. Very promising results in term of maximum specific power density values similar or better than those of standard E-TEK electrode, prepared by conventional powder-type chemical technique, have been obtained for deposition of platinum particles on MWCNTs substrate electrodes, despite the extremely low amount of catalyst (up to 3 times lower than that of commercial electrodes).