Current treatment schemes of childhood cancer are usually effective enough to enable successful management of the disease. With the high rates of survival, another problem arises because patients often suffer much later from side effects of the toxic therapy. A common complication caused by cancer treatment is impairment of the female reproductive system including dysfunction of the hypothalamus and hypophysis, the killing of gonadal cells, and uterine injury. This may lead to altered pubertal timing, gonadotropin insufficiency or deficiency, acute ovarian failure, premature ovarian insufficiency, sexual dysfunction, and complicated pregnancy. The severity of these side effects depends a lot on the patient’s age at treatment and the particularities of their chemo- and/or radiotherapy regimens. While some types of cancer require aggressive treatment, and therefore negative side effects cannot be avoided, strategies which preserve the patient’s reproductive potential are essential. Such strategies are more established in the treatment of adult women, however there are also promising opportunities in the treatment of pediatric oncology patients. Ovar­ian transposition is already widely applied before pelvic radiotherapy. Cryopreservation of ovarian tissue, cryopreservation and in vitro maturation of immature oocytes, or cryopreservation of mature oocytes when the patient’s age is appropriate, have also shown to have promising results in pediatric patients. Concurrent combinations of several techniques can also be successful. Counselling of pediatric patients and their families is challenging, and the urgent commencement of anticancer therapies often discourages attempts to preserve the girl’s reproductive system. Given that successful methods of fertility preserva­tion are already accessible, it is crucial not to leave this topic aside at the time of diagnosis.