Acute mountain sickness is an illness caused by climbing to a high altitude without prior acclimatization. Neurological consequences, like parkinsonism following acute mountain sickness without lesion of brain MRI have been reported rarely. A healthy 56-year-old man presented with dysarthria and gait disturbance. Neurological examination revealed tremor of hands, limb rigidity, and bradykinesia. The symptoms developed approximately 30 days following a 3,500 m climb of the Annapurna in the Himalayas. Brain MRI did not reveal any abnormalities including globus pallidus. The parkinsonism symptoms persisted for about 3 months before a complete recovered was made. We suggest that parkinsonism can develop after climbing to a high altitude but that the symptoms can be transient if a brain MRI detects no abnormalities.