We studied 25 patients with anterior myocardial infarction and two with congestive cardiomyopathy to evaluate two-dimensional echocardiography in the diagnosis of left ventricular thrombi. Five coronary patients had systemic emboli. Four of these patients manifested apical filling defects on cineangiogram, while a levophase cine was equivocal for clot in the fifth patient. Neither echocardiography nor cineangiography visualized ventricular thrombi in the nonembolus coronary patients. Echoes from a distinct apical mass, however, were visualized in all five patients in the embolus group by two-dimensional echocardiography at the cardiac apex. Apical thrombi were confirmed in all four patients in the embolus group undergoing surgery. The irregular configuration of recent thrombi in the coronary patients differed from the circumscribed appearance of chronic thrombi in the cardiomyopathy patients on two-dimensional echocardiogram. Thus, two-dimensional echocardiography can be used to detect and characterize left ventricular thrombi.