Two cases of intracardiac thrombi associated with antiphospholipid antibodies are presented, one in the right atrium and the other in the left ventricle, the latter occurring in the presence of normal left ventricular function. In each, the diagnosis was made by transthoracic echocardiography. Both patients had contraindications to thrombolytic therapy and underwent successful surgical thrombectomy. We suggest that serial transthoracic echocardiography may be warranted in the follow-up of patients with primary hypercoagulable states.