Endometrial stromal sarcomas (ESS) are rare tumors of the uterus. The metastasis of ESS to the cardiac structures is extremely infrequent. Several cases of right-sided heart metastasis have been previously reported. To our knowledge, only one similar case is available in the published studies that presented with recurrent embolic strokes due to left atrial metastasis of ESS. In this report, we describe a 53-year-old woman with endometrial stromal sarcoma; she was referred to our hospital with subacute onset of severe dyspnea and a left atrial mass causing severe mitral stenosis.