Abstract: In this work, zinc oxide (ZnO) nanostructures were synthesized by using zinc chloride and sodium hydroxide as the precursors at different temperatures. The ZnO nanostructures obtained were characterized by X-ray diffraction (XRD), Scanning Electronic Microscopy (SEM), Energy Dispersive X ray Spectroscopy (EDAX).The ZnO powders have hexagonal wurtzite structure and nanometric-sized crystallites. The size of the particle increases as the reaction temperature is increased. An attempt has been made to find out the effect of temperature on the morphology as well as particle size and to optimize the value of temperature for stable smaller sized particles. Once the temperature is optimised effect of base concentration is studied.