Hantavirus cardiopulmonary syndrome (HCPS) is a zoonosis caused by the Andes virus and does not have a specific therapy. Mortality due to Hantavirus infection is high. This increases to more than 60% in critical patients. We evaluated clinical and laboratory markers as predictors in the evolution to severe Hantavirus infection, defined as use of mechanical ventilation (MV) and extracorporeal membrane oxygenation (ECMO) support. Consecutive patients with Hantavirus infection confirmed by serological test or RT-PCR were admitted in the ICU of INT and studied prospectively. Demographic, clinical, and laboratory data, Apache II and SOFA score, transfer time to the ICU, start time of ECMO and MV were collected. Independent risk factors for severe Hantavirus infection were identified by means of logistic regression analysis. The study was approved by the local ethic?s committee. From January 2015 to January 2023, 52 patients were included in the study. The mean age was 36 (SD 14) years; 72% were men. Transfer time to ICU was 20 (SD 26.9) Hours. 16 patients received O2 through the nose, 15 only MV, and 21 MV and ECMO. The global survival was 90%. Multivariate analysis showed that SOFA score on admission is an independent risk factor to the predictor for progression to severe Hantavirus infection (OR, 1.7; 95%CI, 1.0-3.0). The AUC was 0,8920 and the best cutoff point of SOFA score is 6, with 68% sensitivity and 100% specificity. The calculation of SOFA score on admission can help predict progression to severe Hantavirus and early use of ECMO and/or MV.