Objective.-To help the Mountain Rescue Association of Scotland find the best protective mountain rescue casualty bag in cold and windy conditions. The study investigated how 3 different casualty bags (labeled Bag 1, Bag 2, and Bag 3) performed in a cold (- 10degreesC, dry bulb), windy (wind speed 3.0 m.s(-1)) environment using physiological and subjective responses of the participating subjects.Methods.-Eleven mate subjects, aged 23.4 +/- 4 years, percentage body fat 15.5 +/- 2 (mean SD). Each participated in a total of 3 tests (1 for each bag). The tests were scheduled to last 60 minutes. Core and skin temperatures (skin values were measured on the arm. chest, thigh, and calf, and a mean skin temperature was calculated) were measured during the tests. Heart rate, oxygen consumption (Vo(2)), and subjective cold perception ratings were also recorded at regular intervals throughout the test duration. All variables except for Vo(2) and cold discomfort were adjusted for baseline.Results.-There was a significant difference in the mean response between the bags for the following variables: arm, chest, thigh, calf, mean temperature, and cold discomfort.Conclusions.-All 3 bags showed limited ability to protect the subjects in cold, windy conditions. However, the study shows that Bag 2 offered the least protection against the imposed environment, It is difficult to differentiate between the other 2 bags, because Bag 1 performed better than Bag 3 for arm, calf, and mean temperatures, while Bag 3 outperformed Bag 1 for chest and thigh temperatures and cold discomfort scores.