A 65-year-old man developed urinary impairment and gait disturbance over a period of four months. On admission, neurological examinations revealed paraplegia, decreased deep tendon reflexes in the extremities, bilateral positive Babinski and Chaddock signs, superficial and deep sensory disturbances and neurogenic bladder. Cerebrospinal fluid examination disclosed a total cell count of 70/mm3, and protein of 76 mg/dl. Nerve conduction studies and somatosensory evoked potential suggested demyelinating neuropathy and myelopathy. Brain MRI revealed irregular-shaped white matter lesions distributed over the bilateral cerebral hemispheres and the brain stem. In addition spinal MRI disclosed long spinal cord lesions disseminated from the higher cervical to the lower thoracic spine. A 1 microm-thick epon-embedded section and teased fiber preparations of a biopsied sural nerve showed segmental demyelination and remyelination. Treatments using intravenous methylprednisolone and IVIg were both effective. The positive responses to immunological treatment, along with the findings, strongly suggested that the demyelinating lesions occurred in both the central and peripheral nervous systems. We regarded this case as one of chronic progression of Encephalo-myelo-radiculo-neuropathy.