We report the neurophysiological findings from 24 subjects with myotonic dystrophy of Steinert and the histological findings in two of them. The conduction data is compared with that of a group of subjects with Landouzy-Déjérine muscular dystrophy. In 46% of cases, the electrophysiological data revealed slight and generalized axonal neuropathy. Histological results of sural nerve confirmed axonal damage of sensory fibres. The neuropathy was not correlated with age of patients, duration or onset of the disease, nor with the state of the deep reflexes; it did not show signs of progressing and is probably one of the multisystemic manifestations of gene pleiotropism.