We describe 2 patients with associated central and peripheral demyelination. Electrophysiological studies revealed a demyelinating polyneuropathy with sensory and motor conduction blocks. Visual evoked potentials were abnormal. Motor evoked potentials showed abnormal central conduction time in 1 patient. Magnetic resonance imaging revealed regions of abnormal high signal in the spinal cord and brain; sural nerve biopsy disclosed a demyelinating neuropathy. Both patients showed clinical and electrophysiological improvement after steroid therapy.