Methods for the collection and transfer of equine oocytes have been developed, and uses of these techniques have resulted in new clinical and research possibilities. Because oocyte transfer avoids reproductive problems associated with the oviduct, uterus, and cervix, pregnancies can be produced from many mares that can not carry a pregnancy or produce embryos. Oocytes for clinical transfers are usually collected from preovulatory follicles by using transvaginal ultrason-guided follicular aspiration and cultured for a short interval or transferred directly into a recipient's oviduct. For oocyte transfer, the recipient is inseminated within the uterus or served naturally. Sperm and oocyte are transferred into the oviduct where sperm numbers are limited.