Although the clinical symptoms of Machado–Joseph disease (MJD) vary widely, those involving the autonomic nervous system, such as cutaneous sympathetic dysfunction, have rarely been investigated. In addition, there are no reports on cutaneous vasomotor function in patients with MJD. To determine the effects of MJD on cutaneous sympathetic function, we evaluated cutaneous vasomotor and sudomotor responses in the palms of 15 patients (mean age, 49 ± 15 years; seven men and eight women) who were genetically diagnosed with MJD as well as in the palms of 15 age-matched, healthy controls (mean age, 48 ± 16 years; nine men and six women). Sweat response was absent in 10 (67 %) patients with MJD, and the mean amplitude of sweat response was significantly lower (p < 0.0001) in patients with MJD than in healthy controls following mental stress (mental arithmetic) and physiological stimuli. Although vasoconstrictive response was absent in three patients with MJD (20 %), there were no significant differences in the mean amplitude of vasoconstrictive response between patients with MJD and healthy controls. These results indicate that patients with MJD have reduced cutaneous sympathetic response, including severely impaired sudomotor functions and mildly affected vasomotor functions.