There is a higher incidence of demyelinating peripheral neuropathy responsive to immunomodulating treatment in patients with diabetes mellitus. The diagnosis is often overlooked and the patients are given the label of "diabetic neuropathy." Progressive symmetric or asymmetric motor deficit, progressive sensory neuropathy in spite of optimal diabetic control, and unusually high cerebrospinal fluid protein level in "diabetic neuropathy" should alert the clinician to the possibility of an underlying treatable demyelinating peripheral neuropathy masquerading as "diabetic neuropathy."