A 31 year old right handed woman presented with acute onset of aphasia which cleared over two days. CT-scan showed a left middle cerebral artery infarct within Wernicke area. Initial transesophageal two-dimensional echocardiography disclosed a mitral valve lesion suggesting a thrombus. She was discharged on oral anticoagulant treatment. A second stroke occurred ten months later involving left lenticulo-striate arteries area. Echocardiography remain unchanged. Subsequently, giant Lambl's excrescences of mitral valve was confirmed by operation and pathologic examination. The majority of patients with Lambl's excrescences are asymptomatic. However surface thrombus is common with this tumors which reposant a potential us for cerebral embolization. These tumors should be operated since complete excision is the only definitive means of eliminating the source of recurrent embolization.