Transparent zinc oxide (ZnO) films have been grown by galvanostatic cathodic deposition onto conductive glasses from a simple aqueous zinc nitrate electrolyte maintained at 335 K. The as-deposited ZnO films were characterized with Fourier transform infrared absorption spectroscopy, x-ray diffraction, scanning electron microscopy, optical transmission and absorption studies, and measurement of sheet resistivity as a function of cathodic current density. The ZnO films pre pared had a wurtzite structure and exhibited an optical bandgap energy of 3.3 eV which is characteristic of ZnO. At a low cathodic current density of 0.05 mA cm(-2), ZnO films with excellent electrical characteristics have been obtained. A 2 mu m thick ZnO film with an optical transmittance of 72% was deposited by electrolysis for approximately 20 min at a cathodic current density of 10 mA cm(-2).