Antiphospholipid antibodies, i.e. circulating auto-antibodies to negatively charged phospholipids, are mainly observed in patients with systemic lupus erythematosus, but may also occur in individuals who lack evidence of a well-defined systemic disease. Several studies have suggested that they may play a direct role in the pathogenesis of recurrent vascular thrombosis, repeated abortions, and thrombocytopenia (so-called antiphospholipid antibody syndrome), although the mechanism by which this occurs is still poorly understood. The management of patients with antiphospholipid antibody-related thrombosis includes anti-aggregants, anticoagulants, corticosteroids, and cytotoxic drugs, but the optimum treatment is still controversial. Here we review the test systems used to detect antiphospholipid antibodies and their significance in paediatrics.