Thrombophilia can be identified in about half of all patients presenting with venous thrombosis. Testing has increased tremendously for various indications, but whether the results of such tests help in the clinical management of patients has not been settled. Here, we review the most commonly tested thrombophilic abnormalities, i.e. protein C, protein S, and antithrombin deficiencies, the F5 R506Q (factor V Leiden) and F2 G20210A (prothrombin G20210A) mutations, and elevated levels of coagulation factor VIII, and their association with venous and arterial thrombosis as well as pregnancy complications. We conclude that testing for hereditary thrombophilia generally does not alter the clinical management of patients with venous or arterial thrombosis or pregnancy complications. Because testing for thrombophilia only serves limited purpose this should not be performed on a routine basis.