The anti-phospholipid syndrome (APS) was first described in 1983. Anti-phospholipid antibodies form a heterogeneous family that can be detected using a number of immunoreactivity assays. Brain ischemic events in patients with anti-phospholipid antibodies can occur in any vascular territory. Anti-phospholipid antibodies are well established as risk factors in a first ischemic stroke, but their role in recurrent stroke is less clear. Cerebral angiography typically demonstrates intracranial branch or trunk occlusion or is normal in about one-third of patients so studied. Echocardiography (primarily two-dimensional, transthoracic) is abnormal in one-third of patients, typically demonstrating nonspecific left-sided valvular (predominantly mitral) lesions, characterized by valve thickening. Recurrent stroke in patients with livedo reticularis (Sneddon's syndrome) has been associated with anti-phospholipid antibodies. Treatment such as platelet antiaggregant and anticoagulant therapy for secondary stroke prevention have both been used in anti-phospholipid antibody syndrome (AAS) and in cerebrovascular disease associated with antiphospholipid antibody immunoreactivity.