In recent decades, reproductive surgery and medicine have entered a new era of prevention. Oocyte freezing is at the heart of this new era, along with the preservation offemale fertility. Several options are being evaluated, and time will tell which one will prove most suitable for routine use. Currently, only the freezing and transplantation of ovarian tissue seems to have entered clinical practice. Animal studies demonstrated its effectiveness, with pregnancies and births in several species. These studies showed that both slow and rapid freezing (vitrification) allows the survival of more than 80 % of primordial follicles after thawing. Similar results have since been obtained in humans. Freezing allows satisfactory follicular survival Reimplantation of frozen ovarian tissue has helped to restore menstrual cycling and, more importantly, to obtain pregnancies and births, either spontaneously or by IVF This restoration of fertility offers great hopefor female patients having to confront not only their disease but also the prospect of permanent infertility. Related research has led to major advances in biology and reproductive medicine.