Many animal species are endangered or threatened with extinction. However, assisted reproductive techniques can help species that are experiencing reproductive difficulties in captive and wild conditions. Gamete preservation, especially sperm, is one of the effective methods in assisted reproductive techniques. Cryopreservation has been routinely used to preserve sperm of human and different animal species. However, frozen sperm storage for a long time brings many inconveniences because of liquid nitrogen. Many attempts have been made to overcome the disadvantages of the current cryopreservation method. Freeze-drying has been proposed as alternative method for sperm preservation to achieve the ability to store sperm doses indefinitely at ambient temperature or in ordinary refrigerators. Sperm preservation is a useful technique for the maintenance of biological resources in experimental and domestic animals, and in wild animals. In recent years, there has been an increased interest in new preservation techniques that facilitate sperm storage and distribution, with freeze-drying having been proposed as an alternative method for sperm preservation and maintenance of genetic resources in different animal species. This method has been developed that enables sperm to be stored for a long time in a refrigerator at 4°C. Sperms are freeze-dried in a solution containing 10 mM Tris and 1 mM EDTA. Using this method, liquid nitrogen is not required for the storage and transportation of sperm. Valuable sperm samples that are stored in liquid nitrogen might be lost if liquid nitrogen supplies cease, especially during disasters such as earthquakes and typhoons. Freeze-dried sperm can be easily and safely transported worldwide at ambient temperature.In addition, short term preservation at ambient temperature that requires neither liquid nitrogen nor dry ice is possible. At present, it has been reported successfully sperm freeze-drying on many animal species including canine and feli
