The aim of this chapter is to focus on the frozen sections and cryostat. The principle underlying cutting frozen sections is that when the tissue is frozen the water within the tissue turns to ice and in this state the tissue is firm, in which ice acts as embedding medium. Thus, the tissue becomes harder by reducing the temperature and soft by increasing the temperature. The temperature of the tissue block can be altered during section cutting by either using thermomodules (cryostat) or the freezing microtome. The best method of preparing sections of unfixed tissue is by a cryostat. This consists essentially of a moicrotome housed in a deep freeze cabinet, maintained at a temperature of approximately –15°C to –30°C. This chapter covers the theory of freezing, cryoprotectants, cryogen selection, freezing microtome, methods of cutting and frozen sections. In this chapter, questions for exercise and objective type questions are also provided.