Description: A total of 69 sheep and goat embryos at the stage morula or blastocyst produced in vivo from endangered native Bulgarian breeds were recovered, frozen and stored in a cryobank with liquid nitrogen at -196 C. The methods for production, recovery and deep-freezing of the preimplanted embryos are described. The specific hormonal stimulation and possibilities for freezing biotechnology as well as a long-term storage in animal biology science and stock-breeding are discussed. It is well demonstrated that embryo freezing is an approach for conservation of the animal genotype at its current status for a prolonged period