Introduction: Researchers are still searching for a better survive prediction model in the trauma population [1]. Cathepsin D is intracellular protease enrolled in apoptosis, processing of variety enzymes, antigens, hormones and neuropeptides. Plasma concentration of it was markedly increased in multiple injuries [2]. The aim of this study was to elaborate a model/models that are able to predict survive probability in polytrauma using plasmatic activity of cathepsin D (PACD) as covariates. Material & Methods: A prospective research, 63 polytrauma patients (criteria - injury to at least 2 body regions with AIS C 3 and SIRS on at least one day during the first 72 hours [3]). PACD was determined at 3, 6, 12, 24, 48, 72 after traumatic event. Results: Using logistic regression we have created a model (v2(df = 2) = 38.522 p\0.001) that uses the value of PACD at 3 hours and 48 hours after trauma (PACD_3 h and PACD_48 h): p = 1/ (1 + e^(-7.399 + 0.249 x PACD_3 h + 0.207 x PACD_48 h)) where p - probability of survive in polytrauma, e - constant (2.71828) The model has following caracteristics: Nagelkerke R Square = 0.648 (64.8%); Hosmer and Lemeshow Test v2(df = 8) = 4.462, p = 0.813; Sensibility (95.5%, 40 from 42) and Specificity (78.9%, 15 from 19), cut value = 0.51; PACD_3 h (B = -0.249, CI95% -0.561; -0.114), OR = 0.78 (CI95% 0.67-0.91); PACD_48 h (B = -0.207, CI95% 0.501; -0.11), OR = 0.81 (CI95% 0.72-0.92). Conclusions: PACD at 3 hours and 48 hours after trauma can be considered potential biomarkers for survive prediction in polytrauma. The validation of the model follows. References: 1. De Munter L, Polinder S, Lansink KW, Cnossen MC, Steyerberg EW. Mortality prediction models in the general trauma population: a systematic review. Injury 2017; 48: 221–9. 2. Huber-Langa M., Denka S., Fuldab S. Cathepsin D is released after severe tissue trauma in vivo and is capable of generating C5a in vitro. I ˆ n: Molecular Immunology, 2012,50: 60– 65. 3. Butcher N., Enninghorst N., Sisak K., et al. The definition of polytrauma: variable interrater versus intrarater agreement-a prospective international study among trauma surgeons. In: J Trauma Acute Care Surg, 2013 Mar; 74(3): 884-9.