Nanomaterial research has gained importance over the past two decades due to its prospective applications in human life, especially for high performance analytical and medical devices. Nanoparticles made from various organic and inorganic sources continue to play a significant role in the development and usage of these medical devices. The size, shape, surface chemistry as well as surface area to volume ratio help determine the performance of the device they are incorporated into. Therefore, proper knowledge of their physiochemical properties are required to understand their compatibility with other materials or composites. Without characterization techniques, all the necessary information related to the properties of the nanoparticles cannot be obtained. There have been multiple characterization techniques used within the past two decades, with a certain few remaining popular throughout. This chapter will provide a comprehensive account of several popular characterization techniques as well as recent advances utilized for high performance analytical and medical devices. Also discussed in detail are the basic principles and common operational procedures of those techniques. © 2021 Elsevier Inc.