We report the case of a 33-year-old man with a brainstem infarction due to concomitant occlusions in the left internal carotid, both vertebral, and basilar arteries. The patient had experienced a severe Mycoplasma pneumoniae infection about 10 months prior to symptom onset, and his Mycoplasma antibody titre was positive when the stroke occurred. Despite performing meticulous neurological, vascular, and medical evaluations, we were unable to detect other possible causes of the stroke. Therefore, the multiple occlusions in the major cerebral arteries of our patient were concluded to be related to M. pneumoniae infection.