Two cases of intracranial subdural hematoma following lumbar puncture are presented. A review of all previously reported cases shows that subdural hematoma after lumbar puncture is a rare but serious complication. The pathogenesis of subdural hematoma after lumbar puncture is probably related to that of post lumbar puncture headache. Application of an epidural blood patch may therefore be a safe way not only to treat typical post lumbar puncture headache but also to prevent subdural hematoma after lumbar puncture.