Introduction: Severe community-acquired pneumonia (CAP) due to respiratory viruses is highly prevalent in Chile. Common etiologies include Influenza A and B, respiratory syncytial virus (RSV), Hantavirus, and SARS-CoV-2 since 2020. Objective: To identify clinical and laboratory features associated with 20-day mortality in severe viral CAP in a high complexity health care center in southern Chile. Methods: The observational study included two cohorts of patients with severe CAP according to IDSA/ATS criteria: the years 2013-2018 (No COVID-19) and the year 2020 (COVID-19). Sociodemographic, clinical, laboratory, and 30-day mortality data were collected. We used Chi-square and Student's T for categorical and continuous variables. We used a binary logistic regression model for mortality analysis, reporting the results as Odd ratios (ORs). Results: Mortality at 30 days was: Hantavirus 54.4%, Influenza H1N1 36.8%, other influenza 30.4%, RSV 25%, and COVID-19 23.6%. We found no significant difference regarding type of virus (COVID-19 or NO COVID-19). Mortality was associated with older age (OR: 4.6; p-value < 0.01), immunosuppression (OR: 5.8; p-value 0.01), and cyanosis (OR: 3.8, p-value 0.02). Conclusion: COVID-19 was not associated with an increased risk of 30-day mortality compared to other common respiratory viruses in our study. Older age, immunosuppression, and cyanosis were associated with higher risk among patients with severe viral CAP.