Myxoedema coma is a rare endocrine emergency with reported high mortality. Exact incidence is hampered by no clear consensus on its definition and the huge variability in its presentation. Most patients are not comatose, and have a form of severe, decompensated hypothyroidism. The common clinical features, including poor mentation, hypothermia, haemodynamic instability and lethargy, correlate poorly to degree of biochemical hypothyroidism. Early detection and identifying common precipitants which disrupt homeostasis, is important to reduce length of stay and mortality. The evidence to support steroids, leiothyronine versus levothyroxine, and the use of loading doses of treatment will all be discussed.