Exercise in cold environments exerts a unique physiologic stress on the human body, which, under certain conditions, may result in a cold-related injury. Environmental factors are the most important risk factors for the development of hypothermia in athletes. Frostbite occurs as a result of direct cold injury to peripheral tissues. The biggest risk for frostbite is temperature. Trench foot is a result of repeated and constant immersion in cold water. Chilblains are local erythematous or cyanotic skin lesions that develop at ambient air temperatures of 32°F to 60°F after an exposure time of about 1 to 5 h. Cold urticaria is, essentially, an allergic reaction to a cold exposure and can be controlled with avoidance of the cold. There are a number of risk factors and conditions that predispose athletes to cold injury, but exercise in the cold can be done safely with proper education and planning.