A telephone survey was carried out on the use of hypothermia as part of the management of unconscious patients following cardiac arrest admitted to United Kingdom (UK) intensive care units (ICUs). All 256 UK ICUs listed in the Critical Care Services Manual 2004 were contacted to determine how many units have implemented therapeutic hypothermia for unconscious patients admitted following cardiac arrest, how it is implemented, and the reasons for non-implementation. Two hundred and forty-six (98.4%) ICUs agreed to participate. Sixty-seven (28.4%) ICUs have cooled patients after cardiac arrest, although the majority of these have treated fewer than 10 patients. The commonest reasons given for not using therapeutic hypothermia in this situation are logistical or resource issues, or the perceived lack of evidence or consensus within individual ICU teams.