Deep venous thrombosis may result in the clinical syndrome of pulmonary embolus. In rare instances, embolization has occurred, not directly to the pulmonary arterial tree, but to the right atrium or right ventricle. We report herein two cases of right atrial thromboembolization detected by two-dimensional echocardiography, and we review recently reported similar cases. The echocardiographic appearance of right-sided cardiac thromboembolism may be unique and allow precise noninvasive diagnosis. Mortality was five of five in patients receiving no specific therapy, four of eight in medically treated patients, and one of seven in surgically treated patients. From this review, it appears that there is a high mortality associated with this entity, which may be improved by rapid recognition and institution of specific therapy with anticoagulants, thrombolytic agents, or surgery. In select patients with low surgical risk, prompt exploration and removal of the mass may be indicated.