Nanotechnology involves the creation and manipulation of materials at nanoscale levels to create products that exhibit novel properties. Nanomaterials possess increased structural integrity as well as unique mechanical, optical, chemical, electrical and magnetic properties. Because of these unique properties, NP can potentially impact the health of those exposed to them during industrial manufacturing and production. Although the applications and benefits of these engineered nanomaterials are extensively, there is a severe lack of information concerning the human health and environmental implications of occupational exposure during the manufacturing and handling process. As the production and application of ZnO nanoparticles expand, potential human exposure will also increase. In occupational settings, these ZnO nanoparticles may release into the surroundings in aerosol form. NP have been shown to reach the systemic circulation after inhalation, ingestion, or intravenous injection, with further distribution and accumulation in several organs such as lung, liver,spleen, kidneys.Therefore, we have undertaken this work to assess the toxicity of Zinc Oxide nanoparticles in rats