Recently, nano-science becomes the most interest field for researchers, synthesis of metal and metal oxide nanoparticles by different methods become a priority for getting desire nano-size particles. Metal oxide nanoparticles play an important role in the industrial, drug, environment....etc. This book provides new and inexpensive methods for synthesis metal oxide nanoparticles along with their characterizations. The synthesized metal oxide nanoparticles in this book being used as a catalyst for decomposing hydrogen peroxide which gave significant results and adsorbent for adsorption lead metal from agricultural soil along with a new method which was provided for measuring lead ions. Also, metal oxide nancomposite used against bacteria and fungi which was observed as effective antibacterial and antifungal.