Nano-technology is regarded as the science that deals with materials on a nano-scale, and it is believed to be an important factor in the industry revolutions, because it provides potential solutions to numerous challenges. Because of their exceptional properties, nano-materials have various applications across a wide range of sectors; for example, carbon nan-otubes, healthcare, computing, nano-robotics, nano-computers, photovoltaic panels, and battery storage. Advances in characterization techniques have enabled the emergence of nano-materials and the perfect mastering of their synthesis methods. Because of their large surface area, nano-materials are also very promising in the areas of “nanomaterials-based corrosion inhibitors.” Characterizing nano-materials is necessary to determine their characteristics and numerous tools exist to help measure these properties. Nano-materials characterization methods and technologies in use today are discussed in this chapter.