Current knowledge about the pathogenic mechanisms involved in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) supports an autoimmune etiology. Some of the cell and humorally mediated immune responses that contribute to the development of CIDP resemble those implicated in multiple sclerosis (MS). The effector role of circulating antibodies has recently been revisited. In addition, similar to the situation in MS, histopathologic studies support the heterogeneity of disease mechanisms in CIDP, with variants showing axon damage. In addition to intravenous immunoglobulin (IVIg), prednisone, and plasma exchange, immunomodulatory drugs also were used to treat CIDP, although no definitive trial data are available. One class of immunomodulators, interferon beta formulations, has proven efficacy in the treatment of MS, and because of clinical similarities between the two diseases it is attractive to investigate whether some agents that are effective in the treatment of MS would also be effective in CIDP. Preliminary studies have evaluated the effects of interferon beta formulations in the treatment of CIDP, one of which has shown promising results and warrants further investigation.