The technique for obtaining polycrystalline thin films of ZnO by sputtering of the compound has been perfected so that epitaxial films can be obtained on sapphire and CdS. Dependence of the crystalline perfection of the films on substrate temperature, deposition rate, and substrate polish has been studied in detail. Substrate temperatures from 100 ° to 500 °C and deposition rates from 1 to 100 Å/min were studied. Film structure was evaluated by x-ray diffraction and reflection electron diffraction. Electrical and optical measurements were made to determine the resistivity, Hall mobility, optical absorption edge, and refractive index of films. It was found that these properties of the films were very similar to bulk crystal data except for the Hall mobility which was lower by almost two orders of magnitude. The poor mobility is attributed to scattering by defects introduced during the high-energy sputtering process.