The authors define pro-thrombotic states as conditions associated with a high frequency of thrombosis; this association is based on pathogenetic or simply clinical and epidemiological relationships. Thrombophilic states have well-defined, specific causes: antithrombin III, protein C and S and similar deficiencies for inherited thrombophilias, and lupus anticoagulant, antiphospholipid antibodies for the acquired forms. Another identifiable group is made up of several conditions predisposing to thrombosis (CPT) characterized by less specific and multiple mechanisms (e.g. malignancy, inflammatory bowel disease, nephrotic syndrome, diabetes, obesity, etc.). These conditions may induce thrombosis by themselves or contribute to its clinical onset in patients with true thrombophilic states. This is especially the case for patients who are taking contraceptive drugs, are pregnant, have undergone surgery or trauma. The term hypercoagulability states is by no means equivalent to either thrombophilia or CPT. In fact, hypercoagulability may be defined as "activation of blood coagulation" in the presence of specific markers such as fibrinopeptide A and prothrombin fragment F1 + 2. Hypercoagulability is therefore a laboratory rather than a clinical condition and can be a transient feature appearing during certain phases of thrombophilia or CPT. Lastly, conditions involving the presence of hemostatic risk factors for atherothrombosis are simply terms used to describe a statistical-epidemiological relationship between certain hemostatic variables (fibrinogen, factor VII, PAI, etc.) involving the risk of cardiovascular morbidity and mortality but not necessarily indicating a hypercoagulability state.