The Euro-Phospholipid project started in 1999 with a multicentre, consecutive and prospective design. A total cohort of 1000 patients with antiphospholipid syndrome (APS), derived from 13 countries (Belgium, Bulgaria, Denmark, France, Germany, Greece, Hungary, Israel, Italy, the Netherlands, Portugal, Spain and United Kingdom), has been followed since then. This project allowed the identification of the prevalence and characteristics of the main clinical and immunological manifestations at the onset and during the evolution of APS and demonstrated that it is possible to recognize more homogeneous subsets of clinical significance. Patients with APS associated with systemic lupus erythematosus (SLE) had more episodes of arthritis, livedo reticularis and more frequently exhibited thrombocytopenia and leucopenia. Female patients had more episodes of arthritis and livedo reticularis - both connected with the higher prevalence of migraine and SLE-related APS in women, while male patients had more myocardial infarction, epilepsy and lower limb arterial thrombosis. Childhood onset patients presented more episodes of chorea and jugular vein thrombosis, whereas older onset patients were more frequently male and had more strokes and angina pectoris, but less frequently livedo reticularis.