Paradoxical embolization is a rare but well-recognized cause of stroke. Some studies have suggested a link between patent foramen ovale (PFO) and a higher risk of ischemic stroke through this mechanism. PFO is more commonly seen in patients with cryptogenic stroke, but a clear causative relationship between the two is not well established. Other anatomic features associated with a PFO could increase the risk of a recurrent stroke, including an atrial septal aneurysm (ASA), a large PFO, and spontaneous right-to-left shunt at rest. An underlying hypercoagulable state should be ruled out if a PFO is found in a patient with a stroke or transient ischemic attack who has no other identifiable source. Options for secondary prevention in these patients include antiplatelet therapy, anticoagulation, and surgical or endovascular closure. Studies have not shown any advantage of warfarin over aspirin. Surgical closure is a less favorable option because of its high perioperative risks. To date, retrospective studies show variable results of endovascular closure for prevention of stroke. Several randomized prospective studies currently under way are expected to conclusively answer this question. Until these data is available, antiplatelet therapy remains the first-line treatment and endovascular closure should be considered in selected cases.