We report two patients with multifocal demyelinating motor neuropathy whose symptoms improved after immunoglobulin infusion. Clinical signs included atrophy of the tongue and limb muscles, closely resembling that of motor neuron disease. Nerve conduction studies revealed multiple sites of motor conduction block without sensory abnormalities, suggesting selective involvement of motor fibers. Careful documentation of conduction block is required to diagnose this entity, which may be treated with immunoglobulin therapy.