Since the first ascent of Mt. Everest in 1953, tens of thousands of mountaineers have traveled to the Himalayas in pursuit of summits and adventure. Some have been successful, and some have died. It is now feasible to compile data on success and death rates of Himalayan mountaineers, and then to analyze those rates using techniques developed by evolutionary biologists to study natural selection on organisms in the field. After summarizing the extreme physiological challenges climbers endure at high altitude, I evaluate whether the Khumbu Icefall is the most dangerous section on Everest, whether the use of supplemental oxygen enhances survival during descent from the summits of Everest and K2, whether mountaineers are physiological capable of ascending to a higher altitude than Everest, and whether gender and age influence success and death rates on Everest.