For the successful exploitation of bulk metallic glasses (BMGs), it is necessary to characterize them for their structure, their thermal stability, and their different properties. The structure and thermal stability of BMGs were discussed in Chapter 5. The chemical, mechanical, and magnetic properties of BMGs will be discussed in Chapters 7through 9, respectively. The different physical properties of BMGs such as density, specic heat, viscosity, electrical resistivity, thermal expansion, and diffusivity will be discussed in this chapter. Ameasurement of these physical properties will greatly aid in understanding the structural relaxation and the crystallization processes occurring in these metastable materials and their effect on properties.