Background: The implementation of therapeutic hypothermia (TH) into daily clinical practice appears to be slow. We present our experiences with rapid implementation of a simple protocol for TH in comatose out-of-hospital cardiac arrest (OHCA) survivors. Methods: From June 2002, we started cooling pre-hospitally with sport ice packs in the groin and over the neck. In the intensive care unit (ICU), we used ice-water soaked towels over the torso. All patients were endotracheally intubated, on mechanical ventilation and sedated and paralysed. The target temperature was 33 ± 1 °C to be maintained for 12–24 h. We used simple inclusion criteria: (i) no response to verbal command during the ambulance transport independent of initial rhythm and cause of CA; (ii) age 18–80 years; and (iii) absence of cardiogenic shock (SBP < 90 mmHg despite vasopressors). We compared the first 27 comatose survivors with a presumed cardiac origin of their OHCA with 34 historic controls treated just before implementation. Results: TH was initiated in all 27 eligible patients. The target temperature was reached in 24 patients (89% success rate). ICU- and hospital- length of stay did not differ significantly before and after implementation of TH. Hypokalemia (P= 0.001) and insulin resistance (P= 0.025) were more common and seizures (P= 0.01) less frequently reported with the use of TH. The implementation of TH was associated with a higher hospital survival rate (16/27; 59% vs. 11/34; 32%, respectively; P≤ 0.05). Our results indicate a population-based need of approximately seven cooling patients per 100,000 person-years served. Conclusion: Our simple, external cooling protocol can be implemented overnight in any system already treating post-resuscitation patients. It was well accepted, feasible and safe, but not optimal in terms of cooling rate. Neither safety concerns nor costs should be a barrier for implementation of TH.