Cancer remains among the leading causes of death, yet decades of research have yielded significant progress, with many patients cured and enjoying a return to a good quality of life. Unfortunately for many patients, however, chemotherapy used to treat cancer can ablate or reduce fertility. Freezing of oocytes and/or fertilized embryos can provide a means of preserving fertility for these patients, however, in cases where there is emergent need for chemotherapy, or for pre-pubertal patients, this is not an option. As an alternative, many patients have chosen to freeze ovarian tissue before commencing chemotherapy and upon remission, auto-grafting tissue. Although the number of attempts is not clearly documented, relatively few babies (-30) have been reported in over a decade since early attempts, and many studies have indicated that a vital obstacle to overcome in ensuring success of the graft is prompt and complete restoration of blood flow to tissue following transplantation. The long-term goal of this proposal is the improvement of fertility preservation technologies following auto-graft. The objectives are the optimization of parameters for tissue cryopreservation/thawing and the reduction of tissue death in the graft. The central hypothesis is that supplying a ready source of endothelial (blood vessel) cells upon autograft can improve survival of ovarian tissue.