Spinal subdural hematoma (SDH) is a rare cause of acute spinal cord compression. In most cases, these lesions are observed in association with lumbar puncture or spinal anesthesia, coagulation defect, or an underlying vascular malformation. The use of anticoagulant drug is recommended in managing deep vein thrombosis, acute myocardiac infarct, or acute cerebral infarct. But the risk of bleeding in major organs still exists and is increased by the use of multiple anticoagulants and the intensity of anticoagulation. The risk of spinal hematoma is increased in anticoagulated patients who undergo lumbar puncture or spinal anesthesia. But to dates, there are extremely rare cases of spontaneous spinal SDH occurring in patients with anticoagulant therapy when spinal instrumentation is not also being used. With reviewing some of literatures, we present a case of acute spontaneous spinal SDH developed whilereceiving anticoagulant therapy for treating acute cerebral infarct. (J Korean Acad Rehab Med 2008; 32: 730-733)