Endothelin (ET) family comprises three isoforms, ET-1, ET-2 and ET-3 that bind to two receptors ET-A and ET-B. Upon hESC differentiation, ET-1 and ET-B are respectively up- and down-regulated, suggesting a potential role of ETs in hESC biology. Here we show expression of ET receptors in hESC and demonstrate that ET-1 and ET-2 inhibit gap junctional intercellular communication (GJIC), while ET-3 does not. Pre-incubation of the cell cultures with the two specific antagonists of ET-A and ET-B, BQ123 and BQ788 respectively, demonstrate that inhibition of GJIC by ETs is mediated by ET-A. Long-term treatment of hESC with ET-1 indicates no visible effect on hESC maintenance of pluripotency markers, as assessed by expression of the hESC markers Oct-4, GCTM-2 and TG-30. Altogether these data show that hESC are target cells of ETs.