Introduction: Today, whereas hypoxemia and respiratory failure is the major challenging problem in the course of severe COVID-19 pneumonia, to control the disease at a mild-moderate stage or to stop the inflammation by recognizing the cytokine storm early should be the most prominent goal. We aimed to reveal the clinical efficacy and safety of short-term high-dose corticosteroids in severe COVID-19. Material and Methods: This retrospective observational study consisted of 54 patients who were given high-dose steroid (HDS (>250 mg/day methylprednisolone, 3 days.). Low-dose steroid (LDS) therapy (dexamethasone 8 mg ) was applied to all patients. HDS group was reviewed in terms of decreasing hospital mortality and preventing fibrosis development in follow-up. Results: During the observation period, out of 317 severe COVID-19 pneumonia hospitalized, HDS and LDS were administered to 54 and 216 patients, respectively. Higher body mass index, younger age, more oxygen need of patients at admission, and more need for advanced oxygen therapy during hospitalization were found in the HDS group (p<0.001). Furthermore, 18.5% of patients in the HDS group had need transfer to the intensive care unit whereas it was 3.8% in LDS (p<0.001). Additionally, the mortality rate was determined higher in the HDS group (25. 9% vs 9.9%, p<0.001). The HDS group had lower saturated O2 [IQR, 85% (76-89), p <0.001], and higher ferritin at admission. It was found that HDS was given simultaneously with the increased ferritin with deepening lymphopenia on the third and fifth days. There was no difference in fibrosis development between HDS patients receive and not (15.4% vs 26.2%, p=0.11) Conclusion: The use of HDS in hospitalized COVID-19 patients remains unclear. Along with this, our study demonstrated the use of high-dose corticosteroids might not be associated with a lower mortality rate among hospitalized severe COVID-19 patients.