Arterial hypercoagulability can lead to cerebrovascular disease. Common causes of venous thromboembolism, including factor V Leiden, the prothrombin 20210 mutation, deficiencies of proteins C and S, and antithrombin deficiency are not likely to be associated with stroke. Rather, polymorphisms in fibrinogen, the factor XIII gene, and platelet glycoproteins are congenital abnormalities that have been associated with stroke. Similarly, the acquired conditions, lupus anticoagulants, and heparin-induced thrombocytopenia have a strong association with cerebrovascular disease. This article reviews arterial hypercoagulability as a cause of stroke in adults and identifies an appropriate hypercoagulability workup for patients with idiopathic stroke.