This paper discusses the results of a research aimed at investigating the synthesis of nanostructured lead oxide through reaction of lead nitrate solution and sodium hydroxide solution in the presence of constant frequency ultrasonic waves (Sonochemical method) and polyvinyl pyrrolidone (PVP) as structure director. At first, lead hydroxide was obtained in a synthesized solution and then, after filtration, it was dehydrated at the temperature of 320 degrees C so that nanostructured lead oxide can be produced. The effects of different parameters including lead nitrate concentration, sodium hydroxide concentration, synthesis temperature, treatment time and PVP concentration were optimized by a "one at a time" method. The prepared lead oxide powder was characterized by scanning electron microscopy (SEM), transmission electron spectroscopy (TEM) and X-ray diffraction (XRD). Under optimum conditions, uniformed and homogeneous nanostructured lead oxide powder with more spongy morphology and particle size of 20-40 nm was obtained. The synthesized lead oxide, as anode and cathode of lead-acid batteries, showed very excellent discharge capacity (230 mA h g(-1)) and cycle life. (C) 2007 Elsevier B.V. All rights reserved.