Embryonic stem (ES) cells are derived from the inner cell masses of preimplantation embryos. ES cells are pluripotent cells with the capacity for long-term propagation and broad differentiation plasticity. These cells have an exceptional functional feature in that they can differentiate into all tissues and organs, including germ cells. Established ES cell lines have been generated in mouse, human, and nonhuman primate but derivation of ES cells in farm animals has been problematic. Several ES-like cell lines from farm animals have been reported to exhibit properties of pluripotency in vitro. However, only a few of them morphologically resemble ES cells, or express markers that are associated with established ES cell lines from mouse and humans. Methods for derivation, propagation, and differentiation of ES cells from domestic animals have not been fully established. In this chapter, we describe methods for isolation of goat ES (gES) cell lines from in vivo-derived blastocysts and characterization of markers indicative of pluripotency. In addition, we outline differentiation of gES cells into all three germ layers in vivo by forming teratomas as a hallmark of pluripotency.