Ovarian tissue cryopreservation (OTC) is offered to women treated for acute leukemia to preserve their fertility before hematopoietic stem cell transplantation. The risk of leukemic infiltration in ovarian samples harvested before administration of chemotherapy limits ovarian tissue transplantations. We assessed the minimal residual disease (MRD) by sensitive quantitative polymerase chain reaction in cryopreserved ovarian cortex and medulla samples harvested from 30 patients in complete remission of acute leukemia, including 60 % with negative bone marrow MRD at the time of OTC. Ovarian MRD was undetectable in 21 patients (70%), detectable below 10-4 in 8 patients (27%) and between 10-3 and 10-4 in 1 patient (3%). Twenty patients (67%) had concordant MRD between bone marrow and ovarian samples. Interestingly 4 patients had positive MRD in ovarian samples while undetectable in bone marrow. Our results underline the importance of reaching the best control of the disease with undetectable or low MRD levels before OTC to minimize the risk of ovarian leukemic infiltration. The discordant results between ovarian samples and bone marrow require to test the more ovarian samples available before considering ovarian tissue transplantation.Copyright © 2020 American Society of Hematology.