Cardiac thrombus accompanies risk for peripheral embolization, either into the systemic circulation (from the left heart) or into the pulmonary arteries (right heart). In fact, the presence of peripheral emboli should prompt the search for a source within the heart. Echocardiography is the present technique of choice. Also, computed tomography and magnetic resonance imaging may provide additional information. In this article, we will demonstrate various features of cardiac thrombus on computed tomography and magnetic resonance imaging such as mural thrombus after myocardial infarction, thrombus at left atrial appendage in patients with mitral stenosis, thrombus mimicking tumor, organized thrombus containing calcification at left atrium, and compact moderator band mimicking thrombus.