Introduction:The increasing popularity of trekking in alpine regions has drawn attention to high altitude-associated health concerns.Case Report:Here, we report a case of cerebral venous infarction as a consequence of a hypercoagulable state induced by secondary polycythemia as an adaptation to high altitude.Conclusions:When patients present focal neurological symptoms such as hemiparesis in addition to symptoms of acute mountain sickness or high-altitude cerebral edema such as headache, nausea, vomiting, and dizziness, cerebral venous infarction should be considered.