&NA;A case of lumbar spinal subdural hematoma in a patient who had been on anticoagulant therapy is reported. Thus far 19 cases of spinal subdural hematoma have been reported in the literature, the majority in patients with a bleeding diathesis and after a lumbar puncture. Our case is the third reported to be in association with anticoagulant therapy. The hematoma was lumbosacral, in contrast to the usual location in the dorsal‐lumbar area. A possible mechanism for the production of spinal subdural hematoma after a lumbar puncture is discussed. An early decompressive laminectomy and evacuation of the hematoma is the recommended treatment to obtain the best possible recovery of neurological function. (Neurosurgery,5: 614‐616, 1979)