Antiphospholipid antibodies (aPLs) are acquired antibodies against anionic phospholipid containing moieties in cell membranes. Their presence often is associated with the antiphospholipid syndrome (APS), an acquired autoimmune prothrombotic syndrome associated with thrombosis in the arterial and venous circulations, recurrent unexplained fetal loss, and thrombocytopenia. The association of aPLs with other nonthrombotic neurological disorders remains of unclear significance. This article reviews the definition of APS, its clinical presentations, and therapeutic approaches.