Objective: The purpose of this work was to develop methods for successful cryopreservation of human oocytes. Design: Case-controlled study and case report. Setting: Sanatorium Pronatal, Prague. Methods: Propanediol (PrOH)-sucrose was used as cryoprotectant medium for cumulus-free oocytes and stepwise dilution of cryoprotectant post-thaw. Results: The method was used in three patients (38 denuded oocytes) and yielded excellent survival and fertilization rates (89.5% and 73.5% respectively). In all patients embryotransfer was possible, one patient got pregnant and delivered a healthy baby. Conclusion: Our data show that cryopreservation may ensure that the integrity of the human oocyte is adequate for normal fertilization and embryo development.

        Key words: infertility, IVF, oocyte, cryopreservation