We describe two cases in which multiple sclerosis (MS) occurred in association with tomaculous neuropathy, presenting as chronic, distal sensorimotor polyneuropathy. In Case 1, monoclonal gammopathy of undetermined significance with monoclonal IgG lambda reactive against GM1 ganglioside, was also detected. The diagnosis of tomaculous neuropathy was established after sural nerve biopsy. Teased fibers examination revealed focal 'sausage-like' thickenings of the myelin sheaths in intact fibers and in fibers with segmental demyelination. Electron microscopy showed them to be due, mostly, to multiple windings of redundant myelin and concentric apposition of numerous lamellae, in contact with an intact myelin sheath. These are the first reported cases of tomaculous neuropathy in patients with MS. Whether the combination of the two conditions is purely coincidental or suggests the possible causal relation between MS and tomaculous neuropathy, is not certain.