Several batches of zinc oxide (ZnO) nanopowders were obtained using the electrospark method. The samples differed in starting reagents. The electrospark method for producing ZnO nanoparticles is based on using the energy of an electric spark discharge generated between the electrode and the target. The morphology and phase composition of the synthesized samples were studied. The average particle size ranged from 10 to 25 nm. Particle morphology was diverse and represented mainly by flake nanoparticles. We recorded peaks characteristic of zinc and intensive peaks characteristic of ZnO on the X-ray pattern. The calculated sizes corresponded to coherent scattering for the crystalline phases of ZnO. The band gap was calculated for the synthesis of ZnO nanopowders. A slight narrowing of the band gap indicated the predominant crystalline phase in ZnO nanoparticles and an insignificant effect of the surface states of growth defects.