Autoantibodies against nodal and paranodal proteins, such as neurofascin 140/186, neurofascin 155, contactin 1, and contactin-associated protein 1, have been identified in subsets of patients with chronic inflammatory demyelinating polyneuropathy. Their distinctive characteristics including poor response to immunoglobulin led to the establishment of a new disease entity called "autoimmune nodopathies." IgM monoclonal antibodies against myelin-associated glycoproteins cause intractable sensory-dominant demyelinating polyneuropathy. IgM anti-GM1 and IgG anti-LM1 antibodies are associated with multifocal motor neuropathy and chronic inflammatory demyelinating polyneuropathy, respectively. Monoclonal IgM against disialosyl ganglioside epitopes induces chronic ataxic neuropathy with ophthalmoplegia and cold agglutinin.