Two sisters suffering from a hereditary motor-sensory neuropathy (HMSN) are described. A walking disturbance, deformations of foot, muscle atrophy, areflexia of the legs with disturbance of sensibility are detectable of them. Each of them, their motor nerve conduction velocity (NCV) of all extremities was slowed. The younger of the two sisters had graver symptoms and her sural nerve biopsy exhibited a reduced number of myelinated nerve fibres, some distinguished axon-calibre and onion bulb-formations. The relation of those findings to the classification of HMSN is demonstrated and the importance of NCV-measurement to clarification of walking disturbance is shown.