Human embryonic stem (hES) cells are self-renewing and pluripotent, that is, they can differentiate into virtually any somatic cell type. These exquisite features can be harnessed to continually create human cell types in vitro which can otherwise be difficult to obtain from other sources. In the last couple of years, substantial focus has been directed toward the generation and characterization of spontaneously contracting cardiomyocytes from hES cells. Because of their functional properties and human origin, hES cell-derived cardiomyocytes are expected to provide unparalleled opportunities for cardiac drug discovery, cardiac safety assessment of new pharmaceutical compounds and cardiac modeling. This review discusses recent developments and improvements of the differentiated cells and provides some examples of how these cells are beginning to find practical use in drug discovery and development.