Medial medullary infarction is usually manifested as hypoglossal palsy, limb weakness, impairment of proprioception, and oculomotor disturbance. We report a case with the unusual presentation of sensory ataxia. A 71 year-old male presented with ataxia and disequilibrium. Bilateral dysmetria, truncal ataxia, Upbeat nystagmus, and impaired vibration and position sense were the clinical features. However, weakness of the limbs, tongue, or face was not definite. MRI revealed bilateral lesion in the medullary tegmentum, and cortical potentials of somatosensory evoked response were absent. Recovery was fair after treatment. According to the literature, motor weakness is a cardinal manifestation in medial medullary infarction, and there has been no reported case presented as sensory ataxia preserving motor power. Current development of diagnostic tools would contribute to define a variety of clinical manifestations, topography, vascular concomitants, and prognosis in medial medullary infarction.