Two patients were seen with malignant neoplastic emboli to the coronary arteries. One, a 61-year-old woman with a malignant fibrous histiocytoma of the thigh and a solitary pulmonary metastatic lesion, died of an acute myocardial infarction due to a neoplastic coronary embolus after lobectomy. The other, a 51-year-old woman with bronchogenic adenocarcinoma, died of extensive cerebral metastases. At autopsy, she also was found to have had an acute myocardial infarction associated with a neoplastic coronary embolus.