Terminal heart failure is characterized by a significant loss of cardiac myocytes. Stem cells represent a possibility for replacing these lost myocytes but the question of which stem cells are most ideally suited for cell transplantation therapies is still being addressed. Here, we consider human embryonic stem cells (HESC), derived from human embryos in this context. We review the methods used to induce their differentiation to cardiomyocytes in culture, their properties in relation to primary human cardiomyocytes and their ability to integrate into host myocardium. In addition, issues regarding their safety that need addressing before use in cell transplantation therapies, both generally and specifically in relation to the heart, are considered.