Introduction:The likelihood of survival after cancer treatment among young women with cancer has increased considerably, quality of life after treatment has drawn more attention. However, in young fertile women, fertility preservation is an important issue with regard to quality of life. One of the options of fertility preservation is ovarian tissue cryopreservation. The purpose of this follow-up study is to present our clinical experiences and evaluate the long-term follow up of ovarian cryopreservation to improve future patient selection. Material and methods: From July 2002 to December 2015 at the Leiden UniversityHospital, the Netherlands, 69 young women underwent ovarian tissue cryopreservation when they were at risk of iatrogenic premature ovarian insufficiency. Follow-up data with regard to ovarian function were obtained until October 2018, from medical records and questionnaires. Results:Of the 69 women in whom ovarian tissue cryopreservation was performed, 12 died (15.9%), 57 were approached to participate, of which 6 were lost to follow up.The indications for ovarian tissue cryopreservation were malignant (81.1%) and benign (18.9%) diseases in which gonadotoxic treatment was scheduled. In total, twenty women (39.2%) are known to have premature ovarian insufficiency due to gonadotoxic treatment. Fifteen women conceived spontaneously, and delivered 25 babies.In this cohort, the usage rate of autotransplantation is 8.7% (7/69). In total, nine autotransplantations of cryopreserved ovarian tissue were performed in seven patients (of which 1 ovarian tissue cryopreservation was performed in another hospital) after which 6 babies were born to four women, giving a live-birth rate of 57%.Conclusions: Ovarian tissue cryopreservation followed by autotransplantation is an effective method to restore fertility (live-birth rate of 57%). The usage rate of 8.7%