We successfully synthesized metal hydroxide (Ni(OH)(2) and Co(OH)(2)) nanoplates and platinum/nickel hydroxide hybrid nanostructures (Pt/Ni(OH)(2)) in an aqueous solution. Transmission electron microscopy studies of the Pt/Ni(OH)(2) hybrid nanostructures revealed that a number of 3 nm-sized Pt nanoparticles were well dispersed on the surface of each Ni(OH)(2) nanoplate. The Pt/Ni(OH)(2) hybrid nanostructures exhibited enhanced electrocatalytic properties due to synergetic effect of Ni(OH)(2) and Pt.