Aims: To study the impact of hypothermia upon admission to the Intensive Care Unit (ICU) on early and late mortality and to develop a prediction model for late mortality in severely injured trauma patients. Materials and Methods: A multicenter retrospective cohort study was performed in adult trauma patients admitted to the ICU of two Level-1 trauma centers between 2007 and 2012. Hypothermia was defined as a core body temperature of ≤35° Celsius. Logistic regression analyses were performed to quantify the effect of hypothermia on 24-hour and 28-day mortality and to develop a prediction model. Results: A total of 953 patients were included, of which 354 patients had hypothermia (37%) upon ICU admission. Patients were divided into a normothermic or hypothermic group. Hypothermia was associated with a significantly increased mortality at 24 hours and 28 days (OR 2.72 (1.18-6.29 and OR 2.82 (1.83-4.35) resp.). The variables included in the final prediction model were hypothermia, age, APACHE II score (corrected for temperature), INR, platelet count, traumatic brain injury and Injury Severity Score. The final prediction model discriminated between survivors and non-survivors with high accuracy (AUC = 0.871, 95% CI 0.844-0.898). Conclusions: Hypothermia, defined as a temperature ≤35° Celsius, is common in critically ill trauma patients and is one of the most important physiological predictors for early and late mortality in trauma patients. Trauma patients admitted to the ICU may be at high risk for late mortality if the patient is hypothermic, coagulopathic, severely injured and has traumatic brain injury or an advanced age.