Nine Indian men of an arctic village and eight urban white men have been compared in their responses to hand immersion in cold water. Following a 30-minute immersion in warm water (30°C) the hands were placed in cold water in an insulated bath (initially 5°C) for an additional 30 minutes. The rate of heat transfer to the water, finger skin temperatures and skin temperatures over a wrist vein were measured. All subjects were tested in this manner in two environmental situations: clothed in a warm room and unclothed in a cool room. In another experiment six Indians and five whites immersed their right hands in ice water while sitting confortably warm. Generally, the Indians showed a markedly superior ability to maintain hands warm in cold water. Their hands transferred more heat to the water whether the subjects were comfortably warm or chilly. In the cool environment hand heat loss was reduced in both groups, but the calculated heat transfer from circulation alone was still about twice as great in the Indians. The skin temperature measurements reflected the general trends of hand cooling and rewarming. The Indians withstood the hand immersion in ice water with quicker rewarming and less pain than the whites. Although their response is not conserving of metabolic heat, the loss is apparently trivial. The warming of the Indians' hands appears therefore to be adaptive in nature.