question: BACKGROUND: SARS-COV-2 virus that causes COVID-19 binds to the host cell with angiotensin converting enzyme-2 causing acute respiratory distress syndrome (ARDS) and severe mortality and morbidity. There are studies in the literature conducted on the importance of serum angiotensin converting enzyme (ACE) and ACE-2 enzymes in ARDS pathogenesis. Serum ACE levels are higher in children and adolescents than in adults, and COVID-19 has a milder progression. All these reasons suggest that there may be a relationship between serum ACE levels and COVID-19 prognosis. METHODS: The serum ACE levels were determined at the time of hospitalization due to COVID-19 diagnosis in this single-centered, prospective study. According to discharge status, patients were divided into three groups as "Discharge with Healing", "Intensive Care Need" and "Mortality", and the effect of serum ACE levels on disease prognosis was investigated. RESULTS: The present study comprised a total of 103 patients, of whom 42.7% (n = 44) were female, and 57.3% (n = 59) were male. The mean age was 59.48 +/- 16.47;91.3% (n = 94) of them were discharged with healing, 5.8% (n = 6) needed intensive care, and 2.9% (n = 3) resulted in mortality. No differences were detected in terms of serum ACE levels between the groups. CONCLUSIONS: No relationships were detected between serum ACE levels at the time of hospitalization and COVID-19 prognosis.