AbstractMachado‐Joseph disease (MJD) is an autosomal dominant spinocerebellar ataxia. Few studies have examined the neuropsychological and neurobehavioral profiles of patients with MJD. In this study, six individuals with MJD were given a battery of neuropsychological tests. Relative impairments on timed verbal attention tasks and verbal fluency (Stroop, Oral Symbol Digit Modalities, and Controlled Oral Word Association Test) were found. Other executive impairments also were seen on the Wisconsin Card Sorting Test, independent of motor dysfunction severity. Moderate‐ to severe levels of depressive symptoms were endorsed by four of the six patients, and caregivers observed increased apathy in the patients. Impaired executive and emotional functioning in MJD does not appear to be related to ataxia severity. These patients did not meet the criteria for dementia. General cognitive abilities, language, list learning, story recall, and untimed tasks of attention were within normal limits. Impaired executive abilities and emotional functioning in MJD patients is consistent with disruption of frontal‐subcortical systems. © 2002 Movement Disorder Society.