Myxoedema coma is the most lethal manifestation of hypothyroidism. It represents a true medical emergency, especially in the case of cardiovascular instability. Extracorporeal circulation is usually used for rewarming and for providing cardiac support in patients with severe hypothermia and, in addition, cardiovascular instability. We report the case of an 84-year-old woman who presented to the ED with accidental hypothermia associated with myxoedema that was successfully managed by veno-arterial extracorporeal blood rewarming. This case suggests that veno-arterial extracorporeal rewarming appears to achieve a rapid and consistent rewarming rate and is less invasive and more readily available than cardiopulmonary bypass.