The authors describe the clinical, biochemical, electrophysiological and ultrastructural study of a case of Refsum's disease whose phenotype suggested other hereditary ataxias. Due to the presence of Babinski sign and optic atrophy and the absence of retinitis pigmentosa, this case can be considered atypical. Electrophysiological and ultrastructural findings confirm the variability of peripheral lesions in this hereditary polyneuropathy.