Ochratoxin A (OTA) is a mycotoxin produced by different Aspergillus and Penicillium species, and it is considered a common contaminant in food and animal feed worldwide. On the other hand, human embryonic stem cells (hESCs) have been suggested as a valuable model for evaluating drug embryotoxicity. In this study, we have evaluated potentially toxic effects of OTA in hESCs. By using in vitro culture techniques, specific cellular markers, and molecular biology procedures, we found that OTA produces mild cytotoxic effects in hESCs by inhibiting cell attachment, survival, and proliferation in a dose-dependent manner. Thus, we suggest that hESCs provide a valuable human and cellular model for toxicological studies regarding preimplantation stage of human fetal development.