By means of co-electrodeposition, we fabricated 3D assembly of Pt nanostructures with dominant (100) plane on reduced graphene oxide (rGO) modified graphite electrode. The strong metal-support interaction at the atomic level makes the nanostructure highly durable and this modified electrode exhibited high electrocatalytic activity towards methanol oxidation. It has been found that the morphology, active site and the electrochemical activity of Pt are highly dependent on the substrate and the number of electrochemical cycling used for the deposition. rGO-Pt composite deposited using one cycle showed a high mass activity of 2.54 A/mg at 0.67 V for methanol oxidation in acidic condition and 1.84 A/mg at 0.03 V in alkaline medium. This simple and single step approach using electrodeposition to grow the morphology controlled Pt nanostructure on rGO, will aid in the development of active and stable catalyst for fuel cell applications. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.