Antiphospholipid syndrome (APS, Hughes' syndrome) is a systemic autoimmune disorder characterized by arterial and/or venous thrombosis and recurrent foetal loss, accompanied by mild to moderate thrombocytopaenia and elevated titres of antiphospholipid antibodies (aPLs): lupus anticoagulant (LAC) and/or anticardiolipin (aCL) antibodies. APS was defined originally in 1983 in systemic lupus erythematosus (SLE) patients, but later it was found that APS can be primary or secondary to other autoimmune diseases or malignancy. During the past 20 years many organs have been reported to be involved in this syndrome and the clinical manifestations are seen in every medical field. Moreover, many aPLs have been found in APS besides aCLs and LACs, which bind to the autoantigen beta-2-glycoprotein I (beta2GPI). Treatment for APS, based on antiplatelet and anticoagulation drugs, is dependent on various parameters, including whether SLE is also present, classical vs non-classical manifestations of the diseases, women with APS based on pregnancy morbidity, the presence of elevated aCL antibody titres in the absence of clinical manifestations, and catastrophic APS.