Abstract :Stroke is defined as ‘’cryptogenic’’ when a cause can not determined in the diagnostic work-up. It has been demonstrated that cryptogenic strokes account approximately 25% of ischemic strokes. Patent Foramen Ovale (PFO) is a common interatrial structure, which is reported the prevalence approximately 25% in general population. PFO is observed up to 40% of patients with cryptogenic stroke and its prevalence is higher in younger patients. Currently, many studies and authors have been hypothesized that the relationship between PFO and cryptogenic stroke is related to paradoxical embolism via right-to-left atrial shunting of a clinically latent thrombi. The primary prevention for stroke is not recommended in patients with PFO. Antiplatelet or anticoagulan therapy are recommended to all cryptogenic stroke patients with PFO. In these patients, recurrent stroke or TIA are observed despite medical therapy in follow-up. Three large randomized controlled trials comparing percutaneous closure of PFO with medical therapy have not demonstrated clear clinical benefit in terms of recurrent stroke or TIA. Therefore, PFO closure should be considered only in younger patients with PFO and cryptogenic stroke, especially who have anatomical and hemodynamic risk factors such as more than moderate right-to-left atrial shunt and the presence of ASA. Finally, all of these studies indicate that optimal medical therapy and careful patient selection for percutaneous closure of PFO at individual patients.