Metachromatic leukodystrophy is a rare autosomal recessive disorder with deficient arylsulphatase A activity. Different forms occur according to the age at onset of symptoms. Adult forms generally present with presenile dementia and/or psychiatric symptoms. We report a case of a 45-year-old woman, without a family history of neuropsychiatric disorders, presenting with complaints of numbness and weakness of the lower limbs. No intellectual or behavioral disturbances were clinically detectable. Electrophysiological investigation was compatible with severe demyelinating neuropathy in upper and lower limbs. MRI of the brain showed multiple white matter lesions. Adult metachromatic leukodystrophy was diagnosed on the basis of low leucocyte arylsulfatase-A-activity and accumulation of metachromatic material in the sural nerve. Pseudo-deficiency was excluded by DNA analysis. This case indicates that adult metachromatic leukodystrophy should be considered in patients with symptoms and signs resembling multiple sclerosis with peripheral neuropathy and in patients with neuropathy of unknown etiology.