All IVF cycles in which subsequent transfers of thawed pre-embryos occurred were studied. Both age and basal (cycle day 3) FSH level are important determinants of the chance for cryopreservation and the performance of cryopreserved pre-embryos. Although there was no age or FSH level above which pregnancy with frozen pre-embryos was not possible, the chances clearly decline. Thus, consideration to transferring larger numbers of pre-embryos fresh should be given to women in the fifth decade and those with basal FSH > 15 IU/L.