BaCKgRoUND aND aIMS: The coronavirus-19 disease (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 virus, is associated with significant morbidity and mortality attributable to pneumonia, acute respiratory distress syndrome, and multiorgan failure. Liver injury has been reported as a nonpulmonary manifestation of COVID-19, but characterization of liver test abnormalities and their association with clinical outcomes is incomplete. appRoaCH aND ReSUltS: We conducted a retrospective cohort study of 1,827 patients with confirmed COVID-19 who were hospitalized within the Yale-New Haven Health System between March 14, 2020 and April 23, 2020. Clinical characteristics, liver tests (aspartate aminotransferase [AST], alanine aminotransferase [ALT], alkaline phosphatase [ALP], total bilirubin [TBIL], and albumin) at three time points (preinfection baseline, admission, and peak hospitalization), and hospitalization outcomes (severe COVID-19, intensive care unit [ICU] admission, mechanical ventilation, and death) were analyzed. Abnormal liver tests were commonly observed in hospitalized patients with COVID-19, both at admission (AST 66.9%, ALT 41.6%, ALP 13.5%, and TBIL 4.3%) and peak hospitalization (AST 83.4%, ALT 61.6%, ALP 22.7%, and TBIL 16.1%). Most patients with abnormal liver tests at admission had minimal elevations 1-2× the upper limit of normal (ULN; AST 63.7%, ALT 63.5%, ALP 80.0%, and TBIL 75.7%). A significant proportion of these patients had abnormal liver tests prehospitalization (AST 25.9%, ALT 38.0%, ALP 56.8%, and TBIL 44.4%). Multivariate analysis revealed an association between abnormal liver tests and severe COVID-19, including ICU admission, mechanical ventilation, and death; associations with age, male sex, body mass index, and diabetes mellitus were also observed. Medications used in COVID-19 treatment (lopinavir/ritonavir, hydroxychloroquine, remdesivir, and tocilizumab) were associated with peak hospitalization liver transaminase elevations >5× ULN. CoNClUSIoNS: Abnormal liver tests occur in most hospitalized patients with COVID-19 and may be associated with poorer clinical outcomes. (Hepatology 2020;72:1169-1176). C oronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first described in December 2019 in patients with severe pneumonia in Wuhan, China. (1) The World Health Organization declared COVID-19 a global pandemic in March 2020. (2) Although the initial burden of disease was predominantly found in China, (1,3,4,5,6) the United States has reported the most cases of COVID-19 and COVID-19-related death globally since March 26, 2020 and April 11, 2020, respectively. (7) This infection is estimated to have resulted in >11 million cases and 500,000 deaths globally, including 3 million cases and 130,000 deaths in the United States as of July 8, 2020. (7) Whereas patients with COVID-19 typically present with fever and respiratory symptoms consistent