fa Morphometry Morphometry Original Original <strong>Purpose</strong>: To investigate the effect of cardiogel and matrigel on the ultrastructure of embryonic stem cell-derived cardiomyocytes. ECM: Extracellular Matrix derived from cardiac fibroblasts (cardiogel), commercial extracellular matrix (matrigel) and control group (without ECM) were cultured for up to 21 days. Ultrastructural properties of cardiomyocytes were evaluated by transmitting electron microscopy (TEM). On the fourteenth day in cardiomyocytes showed cardiogel and on the twenty-first day of culture in all groups, the above structures appeared.<br> <strong>Conclusion</strong>: The results of this study showed that it is possible to produce mature cardiomyocytes (ultrastructurally) from stem cells Embryonic and fibroblast-derived cardiogels are effective in the faster maturation of embryonic stem cell-derived cardiomyocytes. Embryonic stem cells, Ultrastructure of cardiomyocyte, Cardiogel, Extracellular matrix 1 11 http://anatomyjournal.ir/browse.php?a_code=A-10-304-69&slc_lang=fa&sid=1 Hosein Bahar Vand 10031947532846006795 10031947532846006795 Yes Stem Cell Group, Royant Research Institute, Tehran, Iran. Mehrnaz Azar Nia 10031947532846006796 10031947532846006796 No Kazem Parivar 10031947532846006797 10031947532846006797 No Saeed Kazemi Ashtiani 10031947532846006798 10031947532846006798 No