Heat stroke is a problem that occurs primarily in the out-of-hospital environment. "Cool first, transport second" has been emphasized in consensus statements and systematic reviews regarding the treatment of exertional heat stroke by both EMS and the sports medicine/athletic training communities. However, there remains little guidance on cooling recommendations for the out-of-hospital care of non-exertional heat stroke or classic heat stroke. There is no consensus on the safety or feasibility of cooling classic heat stroke patients in the out-of-hospital environment using cold-water immersion. This case series describes the successful application of on-scene cold-water immersion for five classic heat stroke patients guided by real-time core temperature monitoring.