A laboratory values of 15 patients with severe brain injury, in which was used deliberate mild hypothermia 34 °C during 72 hours as a componentof intensive care management together with standard treatment protocol according to European Brain Injury Consortium, are presented. Surface coolingwas initiated within 15 hours of injury in all patients. Hypothermia to core temperature 34 °C was achieved by forced air cooling in combination withcirculating-water mattress cooling and maintained for 72 hours. After this time were patients rewarmed to 36,5 °C of core temperature. The laboratoryvalues were obtained from 9 examinations of arterial blood in 8 hours period during hypothermia therapy and during normothermia too. For statisticalanalysis was used Wilcoxon test. There were no statistically significant changes in serum levels of PaO2, PaCO2, urea, sodium and glycaemia in thecourse of mild hypothermia therapy compare to normothermia values.