Vasculitis is a rare cause of leg ulceration. It is unclear why severe skin infarction develops in some patients with vasculitis, whereas others have only mild symptoms such as purpura, erythema, or urticaria. A coincidence of vasculitis and hypercoagulability may lead to more extensive thrombotic occlusion and hence explain the occurrence of large ulcers in a subset of patients. Our aim was to investigate whether patients with vasculitis ulcers have an increased incidence of hypercoagulability. Thirteen consecutive patients admitted to the hospital with necrotic ulcers caused by histologically confirmed vasculitis were screened for clotting disorders. In 7 of 13 patients (53%), hypercoagulable conditions were found. Five patients had factor V Leiden (38%), and 2 had lupus anticoagulant (15%). The normal frequency of these conditions is 5% to 6% and 3.6%, respectively. These data indicate that there is an increased incidence of hypercoagulable disorders in patients with vasculitis ulcers. We recommend screening these patients routinely for hypercoagulability.