10% Pt/CDX975 catalyst was prepared by ethylene glycol reduction and stabilization by citrate, for varying citrate/Pt mole ratios of 0, 2.4, 6, 12 and 24, in aqueous solution. X-ray diffraction and Transmission Electron Microscopy studies have shown a decrease in Pt particle size with increase in citrate/Pt mole ratio. Pt nanoparticle size of 2.7 nm was observed for the citrate/Pt mole ratio of 12. The methanol electro-oxidation studies have shown an optimum activity of 202 mA/cm 2 for the system prepared using citrate/Pt mole ratio of 12. X-ray Photoelectron Spectroscopic studies have shown an increase in the existence of Pt(II) state with increase of citrate/Pt mole ratio. The similar trend of Pt(II) state with methanol electro oxidation activity for varying mole ratios of citrate/Pt allows one to presume the, involvement of Pt(II) state in methanol electro-oxidation reaction. © 2011 American Scientific Publishers.