The necessity to cryopreserve human oocytes successfully, with the goal of achieving term pregnancies at rates equivalent to those obtained with fresh oocytes is urgent. Cryopreservation of oocytes is desirable because: 1) it would allow infertility patients to store excess oocytes instead of embryos, eliminating some of the ethical and religious concerns that accompany embryo storage; 2) permit storage of donor oocytes in egg banks, analogous to existing sperm banks. This option would allow the cryopreserved oocytes to be quarantined until screening for infectious diseases is completed, and would also avoid donor-recipient synchronization difficulties; and 3) can help cancer patients preserve their fertility before they face sterilization due to chemotherapy or radiation. Oocyte cryopreservation is therefore gaining in popularity as an option for infertility treatment as well as fertility preservation.