A successfully treated case with a spinal subdural abscess in the lumbar region is reported. The patient, a 58-year-old male, had been suffered from fever and pain in the back for 2 months prior to the visit to a hospital, where pus was obtained through a lumbar puncture. He was then admitted to the Neurosurgical Clinic, Gunma University Hospital on September 6, 1974. On admission, neurological examination revealed an alert patient with flaccid paraparesis, sensory disturbance in bilateral lower limbs and urinary retention. Stiffness of the neck and Lasègue's sign were observed. The body temperature was 38.7 degrees C, white blood cell count 18,900/mn3, and erythrocyte sedimentation rate 118 mn per hour. Pus was again obtained from the spinal canal through a lumbar puncture between the fourth and fifth lumbar vertebrae. Cerebrospinal fluid obtained by a cisternal puncture was colorless clear, and the cell count was 60 WBCs/mn3, protein 154 mg/dl, and glucose 90 mg/dl. Plain roentgenograms of the spine were normal. Myelography showed a block at the level of the first thoracic vertebra, being accompanied with irregular subarachnoid defects. A lumbar laminectomy was performed on September 12, and an abscess adhering to the cauda equina was totally extirpated from the subdural space. Smear of the pus contained Gram-positive bacilli, but the culture was negative. Postoperative course was uneventful, and the neurological deficits were gradually improved. Fifteen months later, the patient could walk with a stick. A review of the available literature, including the present report, lists 14 cases with spinal subdural abscesses which have been induced via hematogenous spread. The symptomotology, clinical diagnosis, treatment and prognosis are briefly discussed. It should be emphasized that early diagnosis and emergency treatment are of choice in order to obtain an excellent operative morbidity.