Ca -mediated signaling is widely spread in nature and plays critical role in the individual development of various organisms ranging from microorganisms to mammals. In vertebrates, Ca is involved in important developmental events: fertilization, body plan establishment, and organogenesis. The two later events are defined by embryonic stem cells (ESCs). ESCs are capable of self-renewal and are pluripotent by nature, that is, can give rise to all types of cells that make up the body. Given the paramount importance of Ca signalization in the development, it is therefore not surprising this process also plays role in the biology of stem cells. In this review, we scrutinize the published experimental data on the role of Ca ions in embryonic stem cells self-renewal and pluripotency. In line with this, we also discuss possible mechanisms of p53 inhibition as a major hindrance to self-renewal of ESCs. Finally, we argue about the role of G-protein-coupled receptors (GPCRs), the largest family of heteromeric transmembrane receptors, and GPCR-mediated signalization in stem cells, and propose the role for the GPCR-G-protein-PLC-Ca -downstream signaling pathway in the regulation of pluripotency of both mouse and human ESCs.