Spontaneous intracranial hypotension (SIH) causes headache in the absence of tissue injury such as trauma, spinal cord injury, surgery, or epidural anesthesia. Epidural blood patch in the epidural space where CSF leakage occurs is effective for treatment of SIH. However, when the leakage site is unknown, administration of autologous blood into the lumbar epidural space could be effective. Here we report on patients who suffered from headache by SIH and could not confirm the leakage site, however, treatment by lumbar epidural blood patch was administered successfully.