Intraventricular thrombosis (usually occurring after myocardial infarction) can lead to embolization, with serious consequences. Angiocardiography and two-dimensional echocardiography both are limited in their ability to detect intraventricular thrombi. Computed tomography (CT) with intravenous administration of contrast material gave excellent definition of intraventricular thrombi in three patients with recent myocardial infarctions and in one patient with a pericardial patch of the right ventricular apex. A ventricular mural thrombus was detected in a dog after an experimentally induced myocardial infarction. CT offers some advantages over contrast ventriculography and echocardiography in detecting intraventricular thrombosis.