The clinical management of the antiphospholipid syndrome is aimed at assessing the thrombotic risk of an individual in order to undertake primary prevention for the asymptomatic subject positive for antiphospholipid antibodies or prophylaxis of major ischaemic events for the patient who has already experienced thrombosis. Lack of immunological parameters with a clear predictive value and the current concept that thrombosis is a multifactorial disease suggest that all the known acquired and genetic thrombotic risk factors should be taken into account in antiphospholipid syndrome. Low-dose aspirin and hydroxychloroquine have been proven useful in primary prevention. While convincing evidence has been provided that aspirin and hydroxychloroquine do not prevent secondary thrombosis, much debate has recently developed on the level of oral anticoagulation needed to guarantee this prevention. Main concerns are also related to duration of anticoagulation therapy, risk of bleeding, and the increased risk of thrombosis as a result of withdrawal of the anticoagulant. Low-molecular-weight heparin has recently emerged as a valid and safe alternative for those conditions that require transient interruption or withdrawal of anticoagulation. Although treatment of the catastrophic antiphospholipid syndrome is largely empirical, the therapeutic approach based on plasmapheresis associated with immunosupression or intravenous immunoglobulin seems to be the most promising. Most attention has recently been paid to the role of oxidative stress in the pathogenesis of antiphospholipid syndrome, as a correlation between lipid peroxidation and antiphospholipid antibodies has been demonstrated. Our studies showed that lipid peroxidation may contribute to the activation of the clotting system observed in antiphospholipid syndrome and that markers of both procoagulant state and increased lipid peroxidation can be modified by experimental antioxidant treatment.