Objective: Ovarian tissue cryopreservation is considered as a useful option to preserve fertility against cytotoxic chemotherapy or radiotherapy. The purpose of this study was to evaluate the change of telomere length and senescence markers during human ovarian tissue cryopreservation. Methods: Ovarian tissues were obtained from patients who underwent benign ovarian surgery with informed consent and IRB approval. Human ovarian tissues were equally divided and prepared for the slow freezing and vitrification. DNA extracted from ovarian tissues using the DNeasy tissue kit (Qiagen, Hilden, Germany) before and after cryopreservation was sent to the commercial company for telomere length measurement. Other senescence markers such as p53, p16INK4a, p21 and pRb antibodies were evaluated using western blot. Results: Ovarian tissues were obtained from five patients and punctured using biopsy punch (Kai Industies C., Ltd, Japan) to make them same size with diameter 4mm and 1 mm thickness. Mean age of patients was 21 +/- 5.24 years old (range from 21 to 34). Ovarian tissues were cryopreserved and thawed 4 weeks after cryopreservation to evaluate the telomere and other senescence markers. Telomere length and senescence markers were evaluated before and after cryopreservation. Mean telomere length was significantly decreased after cryopreservation (10.56 bp +/-0.81 vs 9.46 bp +/- 1.25). In western blot, p53, p16INK4a, and p21 antibodies were increased and pRb was decreased after ovarian tissue cryopreservation. Conclusion: Ovarian tissue cryopreservation and transplantation is regarded as one of promising option for fertility preservation in women diagnosed as cancer. However, we recommend that clinicians should consider that the procedure of ovarian tissue cryopreservation may increase the aging process of ovarian tissue. Further evaluation will be needed to confirm the result of this study. Acknowledgements: This study was supported by the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2016R1C1B3015250 ).