Machado-Joseph disease (MJD) is a spinocerebellar degeneration with a wide phenotypic presentation. A 64-y-old male with a history of gait disability and fasciculations was referred to our unit with the diagnosis of motor neuron disease (MND), which was supported by the presence of upper motor neuron signs and diffuse loss of motor units on electromyography. Trunk and cranial-innervated muscles were clearly affected. Respiratory function was mildly affected. Cerebellar ataxia developed over time and the diagnosis of MJD was confirmed by genetic studies. MJD should be considered in the differential diagnosis of MND.