We describe a 58-year-old Korean woman who developed tremor 4 months ago. Family history was negative. The patient was taking levothyroxine 0.175 mg daily, after thyroidectomy for 1 year. On neurological examination, she showed mild rigidity and bradykinesia, more predominant in left limbs, compared to right limbs. Rest tremor was observed only in left limbs and was more predominant in the leg. Neither postural instability, nor ataxia was checked, while brisk reflexes were present on both lower limbs without pathologic reflexes. The patient had no problem with social activity, although detailed neuropsychological assessment resulted in mild cognitive impairment.