Nanostructured Co-Ni/Co-Ni oxides were electrochemically deposited onto stainless steel electrode by electrochemical method and characterized for their structural and supercapacitive properties. The SEM images indicated that the obtained Co-Ni/Co-Ni oxides had cauliflower-type nanostructure. The X-ray diffraction pattern showed the formation of Co(3)O(4), NiO, Co and Ni. The EDX elemental mapping images indicated that Ni, Co and 0 are distributed uniformly. The deposited Co-Ni/Co-Ni oxides showed good supercapacitive characteristics with a specific capacitance of 331 F/g at 1 mA/cm(2) current density in 1 M KOH electrolyte. A mechanism of the formation of cauliflower-shape Co-Ni/Co-Ni oxides was proposed. A variety of promising applications in the fields such as energy storage devices and sensors can be envisioned from Co-Ni/Co-Ni oxides. (C) 2008 Elsevier Ltd. All rights reserved.