The major steps in cryopreservation are: (1) mixing of cryoprotective agents (CPA) with cells or tissues before cooling; (2) cooling of the cells or tissues at low temperatures at which the metabolic processes of the cells stop; (3) thawing of the cells or tissues; and (4) removal of CPAs from the cells or tissues after thawing. The appropriate use of CPAs is, therefore, important to improve the viability of the sample to be cryopreserved.