We report the clinical, echocardiographic and therapeutic aspects and the evolution of 7 cases of right cardiac migrant thromboembolus in pulmonary embolism (5 M and 2 F, aged 43 to 91). Our data are also compared with all the cases reported in the literature (77 patients). During a sample year (1987) we systematically performed two-dimensional echocardiograms (2D Echo) as early as possible in all the patients admitted to our Coronary Care Unit for suspected pulmonary embolism; among 42 patients the diagnosis of pulmonary embolism was confirmed in 30 out of 42 patients. A relatively high incidence of thromboembolus was found (5/30, 17% in 1987); this finding seems to be relative to the early execution of the 2D Echo study (thromboembolus was found in 4/5 patients when 2D Echo was performed within 20 hours and in only 1/23 when 2D Echo was performed later). The 2D Echo was always evocative of freely floating migrant thromboembolus (6 in right atrium, 1 in right ventricle) and no differential diagnosis with thrombi in situ or other masses was necessary. The therapy for 6 patients hospitalized for pulmonary embolism and surviving the first hours (1 patient died immediately) was: surgical in 1 case, medical in the other 5. Medical therapy consisted only of heparin-calcium in one patient and heparin-calcium + dipyridamole in another because of contra-indications for more aggressive therapy. One patient underwent anticoagulant therapy with i.v. heparin. The remaining two underwent fibrinolytic therapy with urokinase and, afterwards, anticoagulant therapy: in 1 case the therapy was started after the embolization of the mass in the pulmonary artery had occurred; in the other one we observed the progressive reduction of thromboembolus until its disappearance within 5 days without any signs of further embolization. All patients survived and were discharged within 25 days, despite the occurrence of lung embolization in 4 of them. The review of 77 cases reported in the literature shows good outcomes for embolectomy when compared with medical therapy, but almost half of the patients underwent surgical therapy directly. Medical therapy experience, particularly with thrombolytic agents (10 cases in all), is still too scarce to exclude its role, as indeed our experience seems to indicate.