Our present understanding of the syndromes of CIDP and MMN is insufficient to separate them clearly. I believe that MMN is simply a multifocal, predominantly motor variant of CIDP. Furthermore, the highly touted resemblance of MMN to MND has been exaggerated; these syndromes are only superficially similar and can readily be distinguished on clinical and electrophysiologic grounds. MMN is rare but is probably more common than initially believed; certainly, the literature is replete with reports of cases. Further studies are needed to clarify fully the relationship between CIDP and MMN and the role of glycolipid antibodies in MMN and other motor syndromes.