Abstract : Continuous severity assessment of polytrauma patients is critical for triage, quality management, mortality prediction, and trauma research. Existing data stay dubious about final predictive risk assessment. The goal of this study was to develop simple scales for predicting outcome at three time points during the early posttraumatic period for blunt multiple trauma patients with severe thoracic trauma. Multiple trauma patients with severe thoracic trauma (ISS ≥ 16, age ≥ 18, blunt mechanism, two or more injured body regions with AIS thorax ≥ 3) were included in this single-center prospective observational cohort study. The examinations were performed on the 1st-2nd, 3rd-4th and 5th-6th days after the trauma. Multivariate logistic regression analyses were used to identify independent predictors of mortality. On the 1st-2nd day after trauma, risk factors for adverse outcome were identified among the severity of the head injury, RTS score, hemoglobin, total protein, urea and creatinine concentrations. On the 3rd-4th day – among RTS, NISS scores, total protein concentration and WBC, lymphocytes, band and segmented neutrophils counts. On the 5th-6th day – oxygen content, total protein concentration and RBC, monocytes, band neutrophils counts. Based on routine diagnostic tests performed daily in the ICU, the proposed scoring method, based on three regression equations, was developed to estimate the individual mortality risk of blunt multiple trauma patients with severe thoracic trauma during the first 5-6 days after trauma. Depending on the day of the early posttraumatic intensive care, the prognostic value of clinical and laboratory markers varies.