A comprehensive retrospective study analysing the case records of 86 hypothermic elderly patients who were treated according to a standard protocol in our department between 1980 and 1985 is presented. Hypothermia was found to occur not only in the frail, demented and disabled elderly men and women, but also in apparently healthy elderly individuals living with their families and in rest homes (40%). The level of consciousness was not related to the degree of hypothermia but to the underlying pathology. There was no correlation between the severity of hypothermia and mortality. Fatality was less among the group receiving substantial services, but the overall mortality within 48 hours was 36%. Early detection improved survival. Eleven per cent had recurrence of hypothermia and 90% of those who survived hypothermia died within one year. Prolonged duration of hypothermia, high levels of neutrophilia, blood urea and amylase, cardiac arrhythmias and impairment of consciousness were found to be associated with high mortality.