Synthesis of advanced materials as nanopartciles is currently gaining widespread interest in material processing technology. Cobalt ferrite nanoparticles attract great research interests due to their potential application in ferrofluids, data storage, absorbing materials, magnetic fluids, magnetic recording media and magnetic resonance imaging. The structural stability of the cobalt ferrite nanoparticles is essential in all technical applications. In order to achieve highly homogeneous cobalt ferrite nanoparticles and to avoid using the milling process, various techniques, such as chemical co-precipitation, hydrothermal, sol-gel, glass crystallization, microemulsion, citrate precursor, salt melt method have been developed. The synthesis of cobalt ferrite nanoparticles by chemical co-precipitation technique is the focus of this book. As it is well known, chemical co-precipitation is an economical way to produce homogeneous cobalt ferrite nanoparticles. This book covers the detailed study on ferrite nanoparticles and their potential applications in different fields. The contents of this book are useful for the researchers.