Description: Background: Hemorrhagic fever with renal syndrome (HFRS) has become an important public health concern because of the high incidence and mortality rates, and limited treatment and vaccination. Until now, clinical studies on characteristics and outcomes in critical patients with HFRS have been limited. The aim of this study was to observe the clinical characteristics and cumulative proportions surviving and explore the predictive effects and risk factors for prognosis. Methods: A detailed retrospective analysis of clinical records for critical HFRS patients was conducted. The patients enrolled were treated in the centre for infectious diseases, Tangdu Hospital, between January 2008 and August 2012. The clinical characteristics between the survivors and non-survivors were compared by Student's t-test or Chi-square test. The risk clinical factors for prognosis were explored by logistic regression analysis. The predictive effects of prognosis in clinical and laboratory parameters were analyzed by receiver operating characteristic (ROC) curves. The cumulative proportions surviving at certain intervals in the critical patients were observed by Kaplan-Meier survival analysis. Results: Of the 75 patients enrolled, the cumulative proportion surviving was 70.7% at the second week interval, with a 28-day mortality rate of 36.3%. The non-survivors tended to have higher frequencies of agitation, dyspnea, conjunctival hemorrhage, coma, cardiac failure, acute respiratory distress syndrome (ARDS) and encephalopathy (P 〈 .05). ARDS, conjunctival hemorrhage and coma were risk factors for death in the critical patients with HFRS. The non-survivors were found to have lower serum creatinine (Scr) levels (P 〈 .001) and higher incidences of prolonged prothrombin time (PT) (P = .006), activated partial thromboplastin time (APTT) (P = .003) and elevated white blood cells (WBC) levels (P = .005), and the laboratory parameters mentioned above reached statistical significance for predicting prognosis (P 〈 .05). Conclusion: The high fatality in critical patients with HFRS underscores the importance of clinicians' alertness to the occurrence of potentially fatal complications and changes in biochemical status to ensure that timely and systematically supportive treatment can be initiated when necessary.