This review deals with recent developments in chronic inflammatory polyneuropathies which, for the most part, are now amenable to effective treatments including immunosuppressive agents, therapeutic plasmapheresis, high-dose intravenous immunoglobulins and possible interferon-beta. Cell- and antibody-mediated mechanisms are discussed and interpreted against the background of experimental autoimmune neuritis. Antibodies of the immunoglobulin G and immunoglobulin M class have been described directed at various peripheral nervous system antigens. There is now ample evidence that some antibodies influence nerve function by mechanisms other than demyelination. Despite considerable overlap of clinical signs between idiopathic chronic inflammatory demyelinating polyradiculoneuropathy and chronic polyneuritis associated with monoclonal gammopathies or malignancies, we suggest maintaining the traditional separation rather than lumping them together. Some distinctive features have now been elaborated including presentation and response to treatment. Multifocal motor neuropathy is a separate disorder with a multifocal inflammatory demyelinating pathology resembling chronic inflammatory demyelinating polyradiculoneuropathy.