Introduction: Dexamethasone is the first medication that improved survival in patients with Coronavirus disease-2019 (COVID-19); however, the effects of corticosteroids with different cumulative doses on disease outcome must be elucidated. Our study aimed to compare clinical features, hospital mortality, and secondary infections in patients with COVID-19 receiving different cumulative doses of systemic corticosteroids. Materials and Methods: A retrospective, observational study was conducted on patients with COVID-19 admitted to intensive care unit between 21st March 2020 and 20th September 2020 to determine who did not receive systemic corticosteroids, who received low-to-moderate cumulative doses of corticosteroids as recommended by the RECOVERY trial [proposed 6 mg of dexamethasone (equivalent to 32 mg methylprednisolone)] for 10 days (total dose of ≤320 mg of methylprednisolone or equivalent doses of corticosteroids), and who received high cumulative doses of corticosteroids (total dose of >320 mg methylprednisolone equivalent). Results: Among 134 patients, 35 (26%) did not receive systemic corticosteroids, 34 (25%) received low-to-moderate cumulative doses of corticosteroids, and 65 (49%) received high cumulative doses of corticosteroids. Secondary bacterial (31.4% vs. 41.2% and 63.1%, p=0.006) and opportunistic infections (2.9% vs. 5.9% and 21.5%, p=0.011) were more frequently observed in the low-to-moderate- and high-dose corticosteroid groups compared with those in the no corticosteroid group. Hospital mortality was 20% in patients who did not receive steroids and 29.4% and 46.2% in patients who received low-to-moderate and high doses of corticosteroids, respectively (p=0.012). High cumulative doses of systemic corticosteroids were found to be the independent determinant for hospital mortality [Odds ratio (OR): 6.302 (1.856-21.394); p=0.003] and secondary infection [OR: 3.334 (1.313-8.496); p=0.011]. Conclusion: Comparison among patients administered with and without systemic corticosteroids revealed that high cumulative doses may be associated with adverse events in critically ill patients with COVID-19.