A 36-year-old man with a history of migraine headache attempted to hike from Lukla, Nepal, to Mount Everest Base Camp. On the sixth day of hiking, he had a migraine headache. After achieving resolution with typical therapies and rest, he ascended higher. Another headache developed that was interpreted to be a migraine. The headache was treated, and he ascended higher, after which severe symptoms of acute mountain sickness developed, necessitating his evacuation by helicopter. Persons with headaches in daily life may present challenges to diagnosis when traveling to high altitude. Careful evaluation and decision making are needed to achieve proper diagnosis and treatment of acute mountain sickness.