This document is designed to assist in vitro fertility clinics in the management of cryopreserved reproductive tissues stored in cryogenic storage (cryostorage) tanks, based upon scientific principles and laboratory experience related to best practice for safe and reliable storage of cryopreserved reproductive tissue. Embryology and andrology laboratories provide storage of often irreplaceable reproductive tissues such as oocytes, embryos, sperm, and ovarian and testicular tissues, including tissues from cancer patients. All of these reproductive tissues must be maintained under stringent conditions.