In this article selected synthesis routes of ceria based nanoparticles and applications related to their unique redox behaviors are reviewed. The capability to switch valence states for cerium ions in oxides renders ceria a widely used compound in disparate fields, such as catalysis, environmental remediation, and free radical scavenging. Cerium ions can change their electronic charge between [Ce3+] and [Ce4+], which allows to absorb oxygen into the lattice or release it into the surroundings. This reaction occurs according to the environmental conditions, but it can be influenced and altered by ulltraviolet light. Although the exchange of the cation’s valence state is also observed in bulk ceria, the property is most utilized in applications with nanosize particles. The review paper is based on the following patents: US8431506, EP1920832, WO2012036786, US20120070500, US20130251756, US7686976, US8066874, US8252087, US8349764, US8435602, US8568538, US20090302275, US20110124488, US20130195927 and US20130273659.