A 31-year-old man was referred to our hospital because of progressive tremor and clumsiness in his limbs and trunk. His symptoms were started in the right leg then gradually spread to all extremities as well as his trunk for 2 years. Neurological examinations revealed muscle rigidity with resting tremor predominantly right limbs. Akinesia and retropulsion were positive. Neither pyramidal tract sign nor cerebellar ataxia was detected. Genetic testing showed the expansion of SCA8 CTA/CTG repeats as 28/141 repeats. Though moderate expansion (less than 92) of SCA8 repeats has been reported in healthy subjects and patients with various diseases, the extraordinary long expansion of CTA/CTG repeats in SCA8 gene in our patient could be significantly pathological. 600 mg/day of L-DOPA clearly improved his symptoms. Dedicate follow up of the clinical course of our patient and the accumulation of the further cases is essential.