Girls who undergo treatment for cancer are at risk of ovarian hormonal dysfunction and subfertility due to the detrimental effects of some chemotherapeutic agents and/or radiotherapy on the gonads. Consequently, fertility-preserving techniques shouldbe discussed before starting gonadotoxic therapy. Ovarian tissue cryopreservation is currently the only option to preserve fertility in prepubertal girls and should be considered if the risk of premature ovarian failure is high. This promising approach involves the storage of a large number of follicles, which may subsequently be transplanted or cultured to obtain mature ovocytes. The results of ovarian tissue cryopreservation in adults are encouraging: at least twenty children have been born after orthotopic autografting of frozen-thawed ovarian cortex. It has been shown twice that transplantedprepubertal ovarian tissue can induce puberty, confirming the functional capacity of frozen-thawed prepubertal ovarian tissue.