Sperm cryopreservation is the process of freezing and storing sperm cells at cryogenic temperatures, typically in liquid nitrogen at minus 196 degrees Celsius, to preserve their viability indefinitely. It is used by fertility clinics for patients undergoing chemotherapy or radiotherapy, by sperm banks managing donor programmes, by equine and bovine reproduction centres, and by research institutions studying reproductive biology. The process involves controlled-rate freezing with a cryoprotectant medium to prevent ice crystal formation, followed by long-term storage in a liquid nitrogen dewar for cell storage. For specialist storage vessels visit Cryolab.