Aims: Although coronavirus disease 2019 (COVID-19) has spread rapidly worldwide, the implication of pre-existing liver disease on the outcome of COVID-19 remains unresolved. Methods: A total of 1,005 patients who had laboratory-confirmed COVID-19 admitted to five tertiary hospitals in South Korea were included in this study. Clinical outcomes in COVID-19 patients with coexisting liver disease and predictors of disease severity and mortality in COVID-19 were assessed. Results: Of the 47 patients (4.7%) who had liver-related comorbidities, 14 patients (1.4%) had liver cirrhosis. Liver cirrhosis was more common in COVID-19 patients with severe pneumonia than in those with non-severe diseases (4.5% vs. 0.9%, P=0.006). Compared to patients without advanced liver fibrosis, a higher proportion of patients with significant fibrosis (presence of liver cirrhosis or FIB-4 >3.25) needed oxygen therapy; were admitted to the intensive care unit; had septic shock, acute respiratory distress syndrome, acute kidney injury; succumbed to death (P<0.05). Presence of liver cirrhosis and higher FIB-4 value were found to be independent predictors of severe disease (OR 4.52, 95% CI 1.20-17.02, P=0.026; OR 6.09, 95% CI 3.76-9.86, P<0.001) and death (HR 2.86, 95% CI 1.04-9.30, P=0.042; HR 4.30, 95% CI 2.56-7.23, P<0.001) in COVID-19, along with old age and diabetes. FIB-4 index showed a high predictive power for disease severity and mortality of COVID-19 (AUROC=0.858, AUROC=0.870, respectively). Conclusions: This study suggests advanced liver fibrosis is a significant risk factor of COVID-19. Stronger personal protection and more intensive treatment for COVID-19 are recommended in these patients.