Background: Clinical significance of patent foramen ovale (PFO) as a cause of cryptogenic stroke and its appropriate management remains to be elucidated. Methods: We reviewed transesophageal echocardiographic (TEE) images of consecutive patients referred for evaluation of cardiac source of embolism. Hand-agitated saline test as well as Doppler study was done in all patients. Absence of any potential cardiac source of embolism including atrial fibrillation, thrombi, tumor, vegetation, prosthetic mechanical valve and left ventricular aneurysm was prerequisite condition for presumptive diagnosis of cryptogenic stroke. Results: Among 1,030 patients, TEE revealed PFO in 311 patients (30.2%), which was associated with cryptogenic stroke in 165 patients (16.0%). Of those patients with cryptogenic stroke and PFO, warfarin with or without antiplatelet drug was prescribed in 61 patients (37.0%, group 1) and antiplatelet drug alone in 85 patients (51.5%, group 2); the remaining 19 patients (11.5%, group 3) underwent percutaneous closure of PFO. Baseline clinical characteristics including age and risk factor profiles of atherosclerosis were not different among groups. During follow-up (3.5짹2.4 years), significantly higher recurrence rate was observed in antiplatelet alone group (p=0.02). Conclusions: PFO was associated with cryptogenic stroke in significant proportion of patients referred for TEE after stroke and antiplatelet drug alone seems to be an inappropriate treatment option.