Pre-hospital cooling of successfully resuscitated out-of-hospital cardiac arrest patients by rapid intravenous infusion of cold crystalloids has been studied repeatedly. Most often, as much as 30 ml/kg has been administered. Purpose of the study: We decided to assess a pre-hospital cooling effectivity of this cooling approach, having the target dose of 15–20 ml/kg of 4 °C cold normal saline (NS) in the setting of the physician staffed Emergency Medical Service. The impact on the clinical outcome has also been analyzed. Materials and methods: We performed an extension of prospective clinical study with a retrospective control group (PRE-COOL, Pre-hospital Cooling of Cardiac Arrest Patients). A total of 74 patients were planed to be cooled by an intravenous administration of 15–20 ml/kg of 4 °C cold NS during transport to the hospital (TH group). A total of 40 control group patients did not underwent any pre-hospital cooling attempt. Results: In the TH group, administration of 15.0 ± 5.8 ml/kg of 4 °C cold NS was followed by a pre-hospital decrease of TT of 1.5 ± 0.8 °C in 42.0 ± 19.0 min (p Conclusions: Pre-hospital induction of TH by the rapid intravenous administration of cold NS has been shown efficient even with the lower dose of coolant as was investigated in the previous studies. This approach can be associated with a potential improvement of the prognosis of the patients.