This paper gives a survey of our research on the development, cryopreservation, in vitro culture and transplantation of early-stage follicles in the past two decades, relative to those obtained by other researchers. Hereby, attention is specially focussed on findings with ruminants. Apart from our histological, immunocytochemical, viability, biochemical, endocrine, cryostore, in vitro and in vivo data on cow, sheep and goat follicles, some general information on the various in vitro culture, cryopreservation and transplantation techniques is given. We conclude that (i) we are still far away from obtaining fertilizable oocytes from in vitro cultured ruminant early-stage follicles, that can be used for invitro production of healthy embryos or offspring, and (ii) our cryopreservation techniques seem good enough to store ruminant early-stage follicles for an undetermined time without viability impairment, followed by further development after thawing in shortor long-term in vitro cultures or in transplantation experiments.