Introduction: An important cause of cryptogenic strokes is the persistence of patent foramen ovale, especially in association with interatrial septal aneurysm, by paradoxical embolic mechanism. Currently, therapeutic medical, interventional and surgical alternatives are available for prevention of recurrent cerebral embolic events in those cases, but a clear standardization of the indications is still missing. Methods: We present the case of a 62 year old female patient without known risk factors, admitted in the Neurology clinic for brachial monoparesis with complete remission in 24 hours, with a recent thalamic hypodensity identified at cranial CT that established the diagnosis of ischemic stroke. In the absence of identifying a certain etiology of the event, an echocardiogram is requested, which reveals a marqued interatrial septal aneurysm with a possible large bidirectional communication at foramen ovale. The aspect is confirmed by transoesophageal echocardiography, including a contrast probe. In the renewal of the anamnesis, we identified a possible recent episode of deep vein thrombosis and the ultrasonographic examination of the lower limbs certifi ed left posterior tibial veins thrombosis. Results: After the initiation of oral anticoagulant treatment and the discharge, the patient was referred for an intervention of percutaneous closure of foramen ovale with an Amplatzer device, followed by antiplatelet prevention treatment with clopidogrel for at least 3 months and a good clinical and echocardiographic outcome at one, 3 and 6 months, without any residual shunts. Screening tests for thrombophilia were recommended, with a negative result. Conclusions: Although the indications for interventional or surgical closure of the patent foramen ovale are not clearly standardized yet, in cases of large defects, with a history of ischemic stroke with a high probability of paradoxical embolic mechanism, these methods are feasible and efficient in secondary prevention. The subsequent prophylaxis by long term anticoagulation is necessary only in particular cases in which a thromboembolic risk is persistent independently of the presence of patent foramen ovale.