Purpose: Considering the anti-inflammatory effect of atorvastatin and the role of medical comorbidities such as hypertension and coronary artery disease on prognosis of the COVID-19 patients, we aimed to assess the effect of atorvastatin add-on therapy on mortality due to COVID-19. Methods: We conducted a retrospective cohort study, including patients who were hospitalized with confirmed diagnosis of severe COVID-19. Baseline characteristics and related clinical data of patients were recorded. Clinical outcomes consist of in hospital mortality, need for invasive mechanical ventilation and hospital length of stay. COX regression analysis models were used to assess the association of independent factors to outcomes. Results: Atorvastatin was administered for 421 out of 991 patients. The mean age was 61.640±17.003 years. Older age, higher prevalence of hypertension and coronary artery disease reported in patients who received atorvastatin. These patients had shorter hospital length of stay (P=0.001). Based on COX proportional hazard model, in hospital use of atorvastatin was associated to decrease in mortality (HR=0.679, P=0.005) and lower need for invasive mechanical ventilation (HR=0.602, P=0.014). Conclusions: Atorvastatin add-on therapy in patient with severe COVID-19 was associated with lower in hospital mortality and reduced the risk of need for invasive mechanical ventilation which support to continue the prescription of the medication.