BACKGROUND:The purpose of this study was to document the correlation between medical and wilderness training with levels of preparedness for acute mountain sickness (AMS), illness, and injury among backcountry hikers. METHODS:We conducted a cross-sectional, convenience survey in Rocky Mountain National Park in July and August 2015. The study group consisted of 380 hikers who completed a written survey that collected information about demographics, wilderness experience, altitude experience, hiking equipment, communications devices, and trip planning. RESULTS:Factors such as wilderness training (wilderness first aid [WFA], wilderness first responder [WFR], or wilderness emergency medical technician [WEMT]), wilderness experience, and altitude experience all affected hikers' emergency preparedness. Respondents with medical training were more prepared to avoid or respond to AMS (62.3％ vs. 34.3％ [P<0.001]). They were also more prepared to avoid or manage injury/illness than hikers without medical training (37.7％vs. 20.7％ [P=0.003]). Participants with wilderness training were more likely to be prepared to avoid or respond to AMS (52.3％ vs. 36.8％ [P=0.025]) but not significantly more likely to be prepared to manage illness/injury (31.8％ vs. 22.0％ [P<0.11]). Adjusting for experience, wilderness training, age, and gender, we found that medical training was associated with increased preparedness for AMS (OR 2.72; 95％ CI 1.51–4.91) and injury/illness (OR 2.71; 95％ CI 1.5–4.89). CONCLUSION:Medically trained hikers were more likely to be prepared to avoid or manage AMS, medical emergencies, and injuries than their non-medically trained counterparts. Wilderness training increased hikers' preparedness for AMS but did not significantly alter preparedness for illness/injury.