From the first of June 90 to the thirty first of January 94, transesophageal echocardiography was performed in 235 consecutive patients (mean age 56 +/- 16 years), presenting either with cerebral ischemic event (n = 202) or a peripheral arterial embolism (n = 33). All patients had normal echocardiographic and Doppler examinations of the carotid arteries, and transthoracic echocardiography did not show any possible cardiac origin for stroke. Ninety seven patients (41,2%) had documented cardiac disease and/or atrial fibrillation (group 1); 138 patients (58,8%) had no previous cardiovascular history (group 2). Transesophageal echocardiography revealed a possible embolic source in 65,9% of cases (group I) compared with 29,7% of cases in group 2 (p < 0,001). Intracavitary thrombus and spontaneous contrast in the left atrium were detected only in group 1 (21,6% vs 0%, p < 0,001 and 24,7% vs 0%, p < 0,001 respectively). Patent foramen ovale was more frequent in group 2:14,5% of cases vs 4,1% of cases, p < 0,01. There was no significant difference between atheromatous aortic plaques and interatrial septam aneurysm incidence in the two groups. Patent foramen ovale and interatrial septal aneurysm were more frequent in group 2:85% of cases vs 10% of cases in group 1. Transesophageal echocardiography contributes more in patients with a history of cardiac disease. In patients without cardiac disease, patient with foramen ovale and interatrial septal aneurysm were mainly detected; their association represented a risk factor of cerebral ischemic event. Therefore transesophageal echocardiography should be performed in young patients or in case of reccurent event.