Antiphospholipid antibody syndrome is recognized as one of the most important causes of hypercoagulability. Itcan be clinically diagnosed if patients have experienced unexplained recurrent venous or arterial thrombosis,recurrent fetal loss, or thrombocytopenia in the presence of circulating autoantibodies to phospholipids, such asanticardiolipin antibody or lupus anticoagulant. Approximately half of all patients with this syndrome do not haveassociated systemic disease, and their condition is described as primary antiphospholipid antibody syndrome(PAPS). In the remainder, the syndrome is accompanied by systemic lupus erythematosus or other connective tissuediseases, and is known as secondary antiphospholipid syndrome (1). The purpose of this paper is to illustrate thesystemic manifestations of PAPS, focusing on the radiological findings of CT, MR and angiography in clinicallyproven patients.