Five patients, 4 female and 1 male, aged 45 to 73, were observed in myxedema coma between 1984 and 1992. In three patients hypothyroidism was not known. Depressed consciousness, hypothermia, bradycardia and no goiter were common to all and a precipitating factor could be identified in 3 of them. Therapy included L-thyroxine and/or triiodothyronine by nasogastric tube, hydrocortisone and supportive measures. Outcome was good in the 2 patients with known precipitating event, less impaired consciousness and normalization of body temperature by the third day of treatment.